gfx 0.5.0

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## Contributing to gfx-rs

### Communication

General-purpose chat is on [Gitter](https://gitter.im/gfx-rs/gfx-rs). It has all the project activity displayed on the right side for your convenience. Note that it embeds images and gists automatically, so post bare links with discretion.

If you've got the code, making a pull request to discuss things on the way may be more efficient than posting it to the chat.

There is also a [Waffle board](https://waffle.io/gfx-rs/gfx-rs), which you can use conveniently to track the whole picture.

Finally, feel free to hop on [#rust-gamedev](http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust-gamedev).

### Issues

Labels are formatted as "M-render", where "M" is a category among those:
  * **T** = Type: *bug*, *discussion*, *doc*, *feature*, *optimization*, *refactor*
  * **S** = Status: *blocked*, *duplicate*, *invalid*, *ready*, *working*
  * **D** = Difficulty: *easy*, *hard*, *medium*
  * **M** = Module: *device*, *user*, *render*, *structure*

### Code

gfx-rs adheres to [Rust Coding Guidelines](http://aturon.github.io/).