# Objective
- Update winit dependency to 0.29
## Changelog
### KeyCode changes
- Removed `ScanCode`, as it was [replaced by
KeyCode](https://github.com/rust-windowing/winit/blob/master/CHANGELOG.md#0292).
- `ReceivedCharacter.char` is now a `SmolStr`, [relevant
doc](https://docs.rs/winit/latest/winit/event/struct.KeyEvent.html#structfield.text).
- Changed most `KeyCode` values, and added more.
KeyCode has changed meaning. With this PR, it refers to physical
position on keyboard rather than the printed letter on keyboard keys.
In practice this means:
- On QWERTY keyboard layouts, nothing changes
- On any other keyboard layout, `KeyCode` no longer reflects the label
on key.
- This is "good". In bevy 0.12, when you used WASD for movement, users
with non-QWERTY keyboards couldn't play your game! This was especially
bad for non-latin keyboards. Now, WASD represents the physical keys. A
French player will press the ZQSD keys, which are near each other,
Kyrgyz players will use "Цфыв".
- This is "bad" as well. You can't know in advance what the label of the
key for input is. Your UI says "press WASD to move", even if in reality,
they should be pressing "ZQSD" or "Цфыв". You also no longer can use
`KeyCode` for text inputs. In any case, it was a pretty bad API for text
input. You should use `ReceivedCharacter` now instead.
### Other changes
- Use `web-time` rather than `instant` crate.
(https://github.com/rust-windowing/winit/pull/2836)
- winit did split `run_return` in `run_onDemand` and `pump_events`, I
did the same change in bevy_winit and used `pump_events`.
- Removed `return_from_run` from `WinitSettings` as `winit::run` now
returns on supported platforms.
- I left the example "return_after_run" as I think it's still useful.
- This winit change is done partly to allow to create a new window after
quitting all windows: https://github.com/emilk/egui/issues/1918 ; this
PR doesn't address.
- added `width` and `height` properties in the `canvas` from wasm
example
(https://github.com/bevyengine/bevy/pull/10702#discussion_r1420567168)
## Known regressions (important follow ups?)
- Provide an API for reacting when a specific key from current layout
was released.
- possible solutions: use winit::Key from winit::KeyEvent ; mapping
between KeyCode and Key ; or .
- We don't receive characters through alt+numpad (e.g. alt + 151 = "ù")
anymore ; reproduced on winit example "ime". maybe related to
https://github.com/rust-windowing/winit/issues/2945
- (windows) Window content doesn't refresh at all when resizing. By
reading https://github.com/rust-windowing/winit/issues/2900 ; I suspect
we should just fire a `window.request_redraw();` from `AboutToWait`, and
handle actual redrawing within `RedrawRequested`. I'm not sure how to
move all that code so I'd appreciate it to be a follow up.
- (windows) unreleased winit fix for using set_control_flow in
AboutToWait https://github.com/rust-windowing/winit/issues/3215 ; ⚠️ I'm
not sure what the implications are, but that feels bad 🤔
## Follow up
I'd like to avoid bloating this PR, here are a few follow up tasks
worthy of a separate PR, or new issue to track them once this PR is
closed, as they would either complicate reviews, or at risk of being
controversial:
- remove CanvasParentResizePlugin
(https://github.com/bevyengine/bevy/pull/10702#discussion_r1417068856)
- avoid mentionning explicitly winit in docs from bevy_window ?
- NamedKey integration on bevy_input:
https://github.com/rust-windowing/winit/pull/3143 introduced a new
NamedKey variant. I implemented it only on the converters but we'd
benefit making the same changes to bevy_input.
- Add more info in KeyboardInput
https://github.com/bevyengine/bevy/pull/10702#pullrequestreview-1748336313
- https://github.com/bevyengine/bevy/pull/9905 added a workaround on a
bug allegedly fixed by winit 0.29. We should check if it's still
necessary.
- update to raw_window_handle 0.6
- blocked by wgpu
- Rename `KeyCode` to `PhysicalKeyCode`
https://github.com/bevyengine/bevy/pull/10702#discussion_r1404595015
- remove `instant` dependency, [replaced
by](https://github.com/rust-windowing/winit/pull/2836) `web_time`), we'd
need to update to :
- fastrand >= 2.0
- [`async-executor`](https://github.com/smol-rs/async-executor) >= 1.7
- [`futures-lite`](https://github.com/smol-rs/futures-lite) >= 2.0
- Verify license, see
[discussion](https://github.com/bevyengine/bevy/pull/8745#discussion_r1402439800)
- we might be missing a short notice or description of changes made
- Consider using https://github.com/rust-windowing/cursor-icon directly
rather than vendoring it in bevy.
- investigate [this
unwrap](https://github.com/bevyengine/bevy/pull/8745#discussion_r1387044986)
(`winit_window.canvas().unwrap();`)
- Use more good things about winit's update
- https://github.com/bevyengine/bevy/pull/10689#issuecomment-1823560428
## Migration Guide
This PR should have one.
# Objective
- Standardize fmt for toml files
## Solution
- Add [taplo](https://taplo.tamasfe.dev/) to CI (check for fmt and diff
for toml files), for context taplo is used by the most popular extension
in VScode [Even Better
TOML](https://marketplace.visualstudio.com/items?itemName=tamasfe.even-better-toml
- Add contribution section to explain toml fmt with taplo.
Now to pass CI you need to run `taplo fmt --option indent_string=" "` or
if you use vscode have the `Even Better TOML` extension with 4 spaces
for indent
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- Fix adding `#![allow(clippy::type_complexity)]` everywhere. like #9796
## Solution
- Use the new [lints] table that will land in 1.74
(https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#lints)
- inherit lint to the workspace, crates and examples.
```
[lints]
workspace = true
```
## Changelog
- Bump rust version to 1.74
- Enable lints table for the workspace
```toml
[workspace.lints.clippy]
type_complexity = "allow"
```
- Allow type complexity for all crates and examples
```toml
[lints]
workspace = true
```
---------
Co-authored-by: Martín Maita <47983254+mnmaita@users.noreply.github.com>
Preparing next release
This PR has been auto-generated
---------
Co-authored-by: Bevy Auto Releaser <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: François <mockersf@gmail.com>
# Objective
`bevy_a11y` was impossible to integrate into some third-party projects
in part because it insisted on managing the accessibility tree on its
own.
## Solution
The changes in this PR were necessary to get `bevy_egui` working with
Bevy's AccessKit integration. They were tested on a fork of 0.11,
developed against `bevy_egui`, then ported to main and tested against
the `ui` example.
## Changelog
### Changed
* Add `bevy_a11y::ManageAccessibilityUpdates` to indicate whether the
ECS should manage accessibility tree updates.
* Add getter/setter to `bevy_a11y::AccessibilityRequested`.
* Add `bevy_a11y::AccessibilitySystem` `SystemSet` for ordering relative
to accessibility tree updates.
* Upgrade `accesskit` to v0.12.0.
### Fixed
* Correctly set initial accessibility focus to new windows on creation.
## Migration Guide
### Change direct accesses of `AccessibilityRequested` to use
`AccessibilityRequested.::get()`/`AccessibilityRequested::set()`
#### Before
```
use std::sync::atomic::Ordering;
// To access
accessibility_requested.load(Ordering::SeqCst)
// To update
accessibility_requested.store(true, Ordering::SeqCst);
```
#### After
```
// To access
accessibility_requested.get()
// To update
accessibility_requested.set(true);
```
---------
Co-authored-by: StaffEngineer <111751109+StaffEngineer@users.noreply.github.com>
CI-capable version of #9086
---------
Co-authored-by: Bevy Auto Releaser <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: François <mockersf@gmail.com>
I created this manually as Github didn't want to run CI for the
workflow-generated PR. I'm guessing we didn't hit this in previous
releases because we used bors.
Co-authored-by: Bevy Auto Releaser <41898282+github-actions[bot]@users.noreply.github.com>
# Objective
The window event types currently don't support reflection. This PR adds support to them (as requested [here](https://github.com/bevyengine/bevy/issues/6223#issuecomment-1273852329)).
## Solution
Implement `Reflect` + `FromReflect` for window event types. Relevant traits are also being reflected with `#[reflect(...)]` attributes.
Additionally, this PR derives `Reflect` + `FromReflect` for `WindowDescriptor` and the types it depends on so that `CreateWindow` events can be fully manipulated through reflection.
Finally, this PR adds `FromReflect` for `PathBuf` as a value type, which is needed for `FileDragAndDrop`.
This adds the "glam" feature to the `bevy_reflect` dependency for package `bevy_window`. Since `bevy_window` transitively depends on `glam` already, all this brings in are the reflection `impl`s.
## Open questions
Should `app.register_type::<PathBuf>();` be moved to `CorePlugin`? I added it to `WindowPlugin` because that's where it's used and `CorePlugin` doesn't seem to register all the missing std types, but it would also make sense in `CorePlugin` I believe since it's a commonly used type.
---
## Changelog
Added:
- Implemented `Reflect` + `FromReflect` for window events and related types. These types are automatically registered when adding the `WindowPlugin`.
# Objective
- Update `wgpu` to 0.14.0, `naga` to `0.10.0`, `winit` to 0.27.4, `raw-window-handle` to 0.5.0, `ndk` to 0.7.
## Solution
---
## Changelog
### Changed
- Changed `RawWindowHandleWrapper` to `RawHandleWrapper` which wraps both `RawWindowHandle` and `RawDisplayHandle`, which satisfies the `impl HasRawWindowHandle and HasRawDisplayHandle` that `wgpu` 0.14.0 requires.
- Changed `bevy_window::WindowDescriptor`'s `cursor_locked` to `cursor_grab_mode`, change its type from `bool` to `bevy_window::CursorGrabMode`.
## Migration Guide
- Adjust usage of `bevy_window::WindowDescriptor`'s `cursor_locked` to `cursor_grab_mode`, and adjust its type from `bool` to `bevy_window::CursorGrabMode`.
# Objective
Add traits to events in `bevy_input` and `bevy_windows`: `Copy`, `Serialize`/`Deserialize`, `PartialEq`, and `Eq`, as requested in https://github.com/bevyengine/bevy/issues/6022, https://github.com/bevyengine/bevy/issues/6023, https://github.com/bevyengine/bevy/issues/6024.
## Solution
Added the traits to events in `bevy_input` and `bevy_windows`. Added dependency of `serde` in `Cargo.toml` of `bevy_input`.
## Migration Guide
If one has been `.clone()`'ing `bevy_input` events, Clippy will now complain about that. Just remove `.clone()` to solve.
## Other Notes
Some events in `bevy_input` had `f32` fields, so `Eq` trait was not derived for them.
Some events in `bevy_windows` had `String` fields, so `Copy` trait was not derived for them.
Co-authored-by: targrub <62773321+targrub@users.noreply.github.com>
# Objective
> This is a revival of #1347. Credit for the original PR should go to @Davier.
Currently, enums are treated as `ReflectRef::Value` types by `bevy_reflect`. Obviously, there needs to be better a better representation for enums using the reflection API.
## Solution
Based on prior work from @Davier, an `Enum` trait has been added as well as the ability to automatically implement it via the `Reflect` derive macro. This allows enums to be expressed dynamically:
```rust
#[derive(Reflect)]
enum Foo {
A,
B(usize),
C { value: f32 },
}
let mut foo = Foo::B(123);
assert_eq!("B", foo.variant_name());
assert_eq!(1, foo.field_len());
let new_value = DynamicEnum::from(Foo::C { value: 1.23 });
foo.apply(&new_value);
assert_eq!(Foo::C{value: 1.23}, foo);
```
### Features
#### Derive Macro
Use the `#[derive(Reflect)]` macro to automatically implement the `Enum` trait for enum definitions. Optionally, you can use `#[reflect(ignore)]` with both variants and variant fields, just like you can with structs. These ignored items will not be considered as part of the reflection and cannot be accessed via reflection.
```rust
#[derive(Reflect)]
enum TestEnum {
A,
// Uncomment to ignore all of `B`
// #[reflect(ignore)]
B(usize),
C {
// Uncomment to ignore only field `foo` of `C`
// #[reflect(ignore)]
foo: f32,
bar: bool,
},
}
```
#### Dynamic Enums
Enums may be created/represented dynamically via the `DynamicEnum` struct. The main purpose of this struct is to allow enums to be deserialized into a partial state and to allow dynamic patching. In order to ensure conversion from a `DynamicEnum` to a concrete enum type goes smoothly, be sure to add `FromReflect` to your derive macro.
```rust
let mut value = TestEnum::A;
// Create from a concrete instance
let dyn_enum = DynamicEnum::from(TestEnum::B(123));
value.apply(&dyn_enum);
assert_eq!(TestEnum::B(123), value);
// Create a purely dynamic instance
let dyn_enum = DynamicEnum::new("TestEnum", "A", ());
value.apply(&dyn_enum);
assert_eq!(TestEnum::A, value);
```
#### Variants
An enum value is always represented as one of its variants— never the enum in its entirety.
```rust
let value = TestEnum::A;
assert_eq!("A", value.variant_name());
// Since we are using the `A` variant, we cannot also be the `B` variant
assert_ne!("B", value.variant_name());
```
All variant types are representable within the `Enum` trait: unit, struct, and tuple.
You can get the current type like:
```rust
match value.variant_type() {
VariantType::Unit => println!("A unit variant!"),
VariantType::Struct => println!("A struct variant!"),
VariantType::Tuple => println!("A tuple variant!"),
}
```
> Notice that they don't contain any values representing the fields. These are purely tags.
If a variant has them, you can access the fields as well:
```rust
let mut value = TestEnum::C {
foo: 1.23,
bar: false
};
// Read/write specific fields
*value.field_mut("bar").unwrap() = true;
// Iterate over the entire collection of fields
for field in value.iter_fields() {
println!("{} = {:?}", field.name(), field.value());
}
```
#### Variant Swapping
It might seem odd to group all variant types under a single trait (why allow `iter_fields` on a unit variant?), but the reason this was done ~~is to easily allow *variant swapping*.~~ As I was recently drafting up the **Design Decisions** section, I discovered that other solutions could have been made to work with variant swapping. So while there are reasons to keep the all-in-one approach, variant swapping is _not_ one of them.
```rust
let mut value: Box<dyn Enum> = Box::new(TestEnum::A);
value.set(Box::new(TestEnum::B(123))).unwrap();
```
#### Serialization
Enums can be serialized and deserialized via reflection without needing to implement `Serialize` or `Deserialize` themselves (which can save thousands of lines of generated code). Below are the ways an enum can be serialized.
> Note, like the rest of reflection-based serialization, the order of the keys in these representations is important!
##### Unit
```json
{
"type": "my_crate::TestEnum",
"enum": {
"variant": "A"
}
}
```
##### Tuple
```json
{
"type": "my_crate::TestEnum",
"enum": {
"variant": "B",
"tuple": [
{
"type": "usize",
"value": 123
}
]
}
}
```
<details>
<summary>Effects on Option</summary>
This ends up making `Option` look a little ugly:
```json
{
"type": "core::option::Option<usize>",
"enum": {
"variant": "Some",
"tuple": [
{
"type": "usize",
"value": 123
}
]
}
}
```
</details>
##### Struct
```json
{
"type": "my_crate::TestEnum",
"enum": {
"variant": "C",
"struct": {
"foo": {
"type": "f32",
"value": 1.23
},
"bar": {
"type": "bool",
"value": false
}
}
}
}
```
## Design Decisions
<details>
<summary><strong>View Section</strong></summary>
This section is here to provide some context for why certain decisions were made for this PR, alternatives that could have been used instead, and what could be improved upon in the future.
### Variant Representation
One of the biggest decisions was to decide on how to represent variants. The current design uses a "all-in-one" design where unit, tuple, and struct variants are all simultaneously represented by the `Enum` trait. This is not the only way it could have been done, though.
#### Alternatives
##### 1. Variant Traits
One way of representing variants would be to define traits for each variant, implementing them whenever an enum featured at least one instance of them. This would allow us to define variants like:
```rust
pub trait Enum: Reflect {
fn variant(&self) -> Variant;
}
pub enum Variant<'a> {
Unit,
Tuple(&'a dyn TupleVariant),
Struct(&'a dyn StructVariant),
}
pub trait TupleVariant {
fn field_len(&self) -> usize;
// ...
}
```
And then do things like:
```rust
fn get_tuple_len(foo: &dyn Enum) -> usize {
match foo.variant() {
Variant::Tuple(tuple) => tuple.field_len(),
_ => panic!("not a tuple variant!")
}
}
```
The reason this PR does not go with this approach is because of the fact that variants are not separate types. In other words, we cannot implement traits on specific variants— these cover the *entire* enum. This means we offer an easy footgun:
```rust
let foo: Option<i32> = None;
let my_enum = Box::new(foo) as Box<dyn TupleVariant>;
```
Here, `my_enum` contains `foo`, which is a unit variant. However, since we need to implement `TupleVariant` for `Option` as a whole, it's possible to perform such a cast. This is obviously wrong, but could easily go unnoticed. So unfortunately, this makes it not a good candidate for representing variants.
##### 2. Variant Structs
To get around the issue of traits necessarily needing to apply to both the enum and its variants, we could instead use structs that are created on a per-variant basis. This was also considered but was ultimately [[removed](71d27ab3c6) due to concerns about allocations.
Each variant struct would probably look something like:
```rust
pub trait Enum: Reflect {
fn variant_mut(&self) -> VariantMut;
}
pub enum VariantMut<'a> {
Unit,
Tuple(TupleVariantMut),
Struct(StructVariantMut),
}
struct StructVariantMut<'a> {
fields: Vec<&'a mut dyn Reflect>,
field_indices: HashMap<Cow<'static, str>, usize>
}
```
This allows us to isolate struct variants into their own defined struct and define methods specifically for their use. It also prevents users from casting to it since it's not a trait. However, this is not an optimal solution. Both `field_indices` and `fields` will require an allocation (remember, a `Box<[T]>` still requires a `Vec<T>` in order to be constructed). This *might* be a problem if called frequently enough.
##### 3. Generated Structs
The original design, implemented by @Davier, instead generates structs specific for each variant. So if we had a variant path like `Foo::Bar`, we'd generate a struct named `FooBarWrapper`. This would be newtyped around the original enum and forward tuple or struct methods to the enum with the chosen variant.
Because it involved using the `Tuple` and `Struct` traits (which are also both bound on `Reflect`), this meant a bit more code had to be generated. For a single struct variant with one field, the generated code amounted to ~110LoC. However, each new field added to that variant only added ~6 more LoC.
In order to work properly, the enum had to be transmuted to the generated struct:
```rust
fn variant(&self) -> crate::EnumVariant<'_> {
match self {
Foo::Bar {value: i32} => {
let wrapper_ref = unsafe {
std::mem::transmute::<&Self, &FooBarWrapper>(self)
};
crate::EnumVariant::Struct(wrapper_ref as &dyn crate::Struct)
}
}
}
```
This works because `FooBarWrapper` is defined as `repr(transparent)`.
Out of all the alternatives, this would probably be the one most likely to be used again in the future. The reasons for why this PR did not continue to use it was because:
* To reduce generated code (which would hopefully speed up compile times)
* To avoid cluttering the code with generated structs not visible to the user
* To keep bevy_reflect simple and extensible (these generated structs act as proxies and might not play well with current or future systems)
* To avoid additional unsafe blocks
* My own misunderstanding of @Davier's code
That last point is obviously on me. I misjudged the code to be too unsafe and unable to handle variant swapping (which it probably could) when I was rebasing it. Looking over it again when writing up this whole section, I see that it was actually a pretty clever way of handling variant representation.
#### Benefits of All-in-One
As stated before, the current implementation uses an all-in-one approach. All variants are capable of containing fields as far as `Enum` is concerned. This provides a few benefits that the alternatives do not (reduced indirection, safer code, etc.).
The biggest benefit, though, is direct field access. Rather than forcing users to have to go through pattern matching, we grant direct access to the fields contained by the current variant. The reason we can do this is because all of the pattern matching happens internally. Getting the field at index `2` will automatically return `Some(...)` for the current variant if it has a field at that index or `None` if it doesn't (or can't).
This could be useful for scenarios where the variant has already been verified or just set/swapped (or even where the type of variant doesn't matter):
```rust
let dyn_enum: &mut dyn Enum = &mut Foo::Bar {value: 123};
// We know it's the `Bar` variant
let field = dyn_enum.field("value").unwrap();
```
Reflection is not a type-safe abstraction— almost every return value is wrapped in `Option<...>`. There are plenty of places to check and recheck that a value is what Reflect says it is. Forcing users to have to go through `match` each time they want to access a field might just be an extra step among dozens of other verification processes.
Some might disagree, but ultimately, my view is that the benefit here is an improvement to the ergonomics and usability of reflected enums.
</details>
---
## Changelog
### Added
* Added `Enum` trait
* Added `Enum` impl to `Reflect` derive macro
* Added `DynamicEnum` struct
* Added `DynamicVariant`
* Added `EnumInfo`
* Added `VariantInfo`
* Added `StructVariantInfo`
* Added `TupleVariantInfo`
* Added `UnitVariantInfo`
* Added serializtion/deserialization support for enums
* Added `EnumSerializer`
* Added `VariantType`
* Added `VariantFieldIter`
* Added `VariantField`
* Added `enum_partial_eq(...)`
* Added `enum_hash(...)`
### Changed
* `Option<T>` now implements `Enum`
* `bevy_window` now depends on `bevy_reflect`
* Implemented `Reflect` and `FromReflect` for `WindowId`
* Derive `FromReflect` on `PerspectiveProjection`
* Derive `FromReflect` on `OrthographicProjection`
* Derive `FromReflect` on `WindowOrigin`
* Derive `FromReflect` on `ScalingMode`
* Derive `FromReflect` on `DepthCalculation`
## Migration Guide
* Enums no longer need to be treated as values and usages of `#[reflect_value(...)]` can be removed or replaced by `#[reflect(...)]`
* Enums (including `Option<T>`) now take a different format when serializing. The format is described above, but this may cause issues for existing scenes that make use of enums.
---
Also shout out to @nicopap for helping clean up some of the code here! It's a big feature so help like this is really appreciated!
Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
# Objective
Fixes#3180, builds from https://github.com/bevyengine/bevy/pull/2898
## Solution
Support requesting a window to be closed and closing a window in `bevy_window`, and handle this in `bevy_winit`.
This is a stopgap until we move to windows as entites, which I'm sure I'll get around to eventually.
## Changelog
### Added
- `Window::close` to allow closing windows.
- `WindowClosed` to allow reacting to windows being closed.
### Changed
Replaced `bevy::system::exit_on_esc_system` with `bevy:🪟:close_on_esc`.
## Fixed
The app no longer exits when any window is closed. This difference is only observable when there are multiple windows.
## Migration Guide
`bevy::input::system::exit_on_esc_system` has been removed. Use `bevy:🪟:close_on_esc` instead.
`CloseWindow` has been removed. Use `Window::close` instead.
The `Close` variant has been added to `WindowCommand`. Handle this by closing the relevant window.
# Objective
- there are a few new versions for `ron`, `winit`, `ndk`, `raw-window-handle`
- `cargo-deny` is failing due to new security issues / duplicated dependencies
## Solution
- Update our dependencies
- Note all new security issues, with which of Bevy direct dependency it comes from
- Update duplicate crate list, with which of Bevy direct dependency it comes from
`notify` is not updated here as it's in #2993
Objective
During work on #3009 I've found that not all jobs use actions-rs, and therefore, an previous version of Rust is used for them. So while compilation and other stuff can pass, checking markup and Android build may fail with compilation errors.
Solution
This PR adds `action-rs` for any job running cargo, and updates the edition to 2021.
This relicenses Bevy under the dual MIT or Apache-2.0 license. For rationale, see #2373.
* Changes the LICENSE file to describe the dual license. Moved the MIT license to docs/LICENSE-MIT. Added the Apache-2.0 license to docs/LICENSE-APACHE. I opted for this approach over dumping both license files at the root (the more common approach) for a number of reasons:
* Github links to the "first" license file (LICENSE-APACHE) in its license links (you can see this in the wgpu and rust-analyzer repos). People clicking these links might erroneously think that the apache license is the only option. Rust and Amethyst both use COPYRIGHT or COPYING files to solve this problem, but this creates more file noise (if you do everything at the root) and the naming feels way less intuitive.
* People have a reflex to look for a LICENSE file. By providing a single license file at the root, we make it easy for them to understand our licensing approach.
* I like keeping the root clean and noise free
* There is precedent for putting the apache and mit license text in sub folders (amethyst)
* Removed the `Copyright (c) 2020 Carter Anderson` copyright notice from the MIT license. I don't care about this attribution, it might make license compliance more difficult in some cases, and it didn't properly attribute other contributors. We shoudn't replace it with something like "Copyright (c) 2021 Bevy Contributors" because "Bevy Contributors" is not a legal entity. Instead, we just won't include the copyright line (which has precedent ... Rust also uses this approach).
* Updates crates to use the new "MIT OR Apache-2.0" license value
* Removes the old legion-transform license file from bevy_transform. bevy_transform has been its own, fully custom implementation for a long time and that license no longer applies.
* Added a License section to the main readme
* Updated our Bevy Plugin licensing guidelines.
As a follow-up we should update the website to properly describe the new license.
Closes#2373
