* The PIXI.BaseTexture.imageUrl property has been removed, as it was never actually populated.
* The PIXI.BaseTexture._UID property has been removed, as it was never actually used internally.
* All references to PIXI.BaseTextureCache have been removed (primarily from BaseTexture.destroy and Texture.destroy), as the BaseTextureCache was never used internally by Phaser, or by our custom version of Pixi.
* PIXI.TextureCache has been removed. It was only ever used by the __default and __missing images that Phaser generates on start-up. It wasn't used internally by Phaser anywhere else, and the only references Pixi has to it have all been removed. If you need it in your own game, please refactor it to avoid it, or re-create the object on the PIXI global object.
* Canvases created by `BaseTexture.fromCanvas` no longer have the `_pixiId` property attached to them, as this was never used internally by Phaser or Pixi.
* PIXI.BaseTexture.updateSourceImage is now deprecated. Please use `Sprite.loadTexture` instead.
* The property PIXI.BaseTextureCacheIdGenerator has been removed, as it is no longer used internally by Phaser or Pixi.
* PIXI.Texture.addTextureToCache has been removed. The PIXI Texture Cache was never actually used by Phaser, and was leading to complications internally.
* PIXI.Texture.removeTextureFromCache has been removed. The PIXI Texture Cache was never actually used by Phaser, and was leading to complications internally.
* PIXI.Texture.fromFrame and PIXI.Sprite.fromFrame have been removed. They relied on the PIXI Texture Cache, which was never actually used by Phaser, and was never used internally by Pixi either.
* The property PIXI.TextureCacheIdGenerator has been removed, as it was not used internally.
* The property PIXI.FrameCache has been removed, as it was not used internally.
There are a bunch of signals added for Sprites; more when input is
enabled. However, very few of these signals are ever actually used. While
the previous performance update related to Signals addressed the size of
each Signal object, this update is to reduce the number of Signal objects
as used by the Events type.
As a comparison the "Particle: Random Sprite" demo creates 3200+ Signals;
with this change there less than 70 signals created when running the same
demo. (Each Event creates at 8 signals by default, and there is an Event
for each of the 400 particles.) While this is an idealized scenario, a
huge amount (of albeit small) object reduction should be expected.
It does this by creating a signal proxy property getter and a signal
dispatch proxy. When the event property (eg. `onEvent`) is accessed a new
Signal object is created (and cached in `_onEvent`) as required. This
ensures that no user code has to perform an existance-check on the event
property first: it just continues to use the signal property as normal.
When the Phaser game code needs to dispatch the event it uses
`event.onEvent$dispath(..)` instead of `event.onEvent.dispatch(..)`. This
special auto-generated method automatically takes care of checking for if
the Signal has been created and only dispatches the event if this is the
case. (If the game code used the `onEvent` property itself the event
deferal approach would be defeated.)
This approach is designed to require minimal changes, not negatively
affect performance, and reduce the number of Signal objects and
corresponding Signal/Event resource usage.
The only known user-code change is that code can add to signal (eg.
onInput) events even when input is not enabled - this will allow some
previously invalid code run without throwing an exception.
Animation.previous will rewind to the previous frame in the animation, even if it's not currently playing. You can optionally define the number of frames to rewind, but the default is 1. This is also aliased from the AnimationManager, so you can do `Sprite.animations.previous()`.
Sprite.updateCrop is available if you wish to update an externally referenced crop rectangle.
Sprites and Images now have their own textures objects, they are no longer references to those stored in the global Pixi.TextureCache. This allows you to redefine the texture frame dynamically without messing up any other Sprites in your game, such as via cropping. They still share global Base Textures, so image references are kept to a minimum.
Sprite.resetFrame will revert the Sprites texture frame back to its defaults dimensions. This is called when you call Sprite.crop with no rectangle, to reset the crop effect, but can be userful in other situations so we've left it as a public method.
AnimationManager.add documentation said that 'frames' could be null, but the code couldn't handle this so it defaults to an empty array if none given (thanks yig)
Also updated TypeScript definitions and StateManager.add docs.
