* Fix compilation with `#[deny(warnings)]` with the `!` type (https://github.com/rust-lang/rust/pull/49039#issuecomment-376420816) by [@TeXitoi](https://github.com/TeXitoi)
* Work around breakage when `proc-macro2`'s nightly feature is enabled. ([#77](https://github.com/Texitoi/structopt/pull/77) and [proc-macro2#67](https://github.com/alexcrichton/proc-macro2/issues/67)) by [@fitzgen](https://github.com/fitzgen)
There was no reason to take the argument by value. Most of the StructOpt users will not be impacted by this change. If you are using `StructOpt::from_clap`, just add a `&` before the argument.
### Fail if attributes are not used by [@TeXitoi](https://github.com/TeXitoi)
StructOpt was quite fuzzy in its attribute parsing: it was only searching for interresting things, e. g. something like `#[structopt(foo(bar))]` was accepted but not used. It now fails the compilation.
You should have nothing to do here. This breaking change may highlight some missuse that can be bugs.
In future versions, if there is cases that are not highlighed, they will be considerated as bugs, not breaking changes.
### Use `raw()` wrapping instead of `_raw` suffixing by [@TeXitoi](https://github.com/TeXitoi)
The syntax of raw attributes is changed to improve the syntax.
You have to change `foo_raw = "bar", baz_raw = "foo"` by `raw(foo = "bar", baz = "foo")` or `raw(foo = "bar"), raw(baz = "foo")`.
* Fix bugs [#24](https://github.com/TeXitoi/structopt/issues/24) and [#25](https://github.com/TeXitoi/structopt/issues/25) by [@TeXitoi](https://github.com/TeXitoi)
* Support of methods with something else that a string as argument thanks to `_raw` suffix by [@Flakebi](https://github.com/Flakebi)