416: Makefile package command and travis github releases r=kvark a=Korijn
Closes#414
Approach mostly mimicked from [gfx-portability](https://github.com/gfx-rs/portability) as recommended to me by @kvark. I needed a number of commits to iron out some kinks for the Windows builds, so I would recommend using squash merge when accepting this PR.
Note that the Windows rust=nightly build fails, but it's also broken on master, so it's unrelated to the changes in this PR.
/cc @almarklein
# Questions
- [x] Would it make sense to also regenerate the `ffi/wgpu.h` and `wgpu-remote.h` header files and include them in the zip archive?
# Todo for maintainers
- [x] Configure encrypted `api_key`
As in [gfx-portability](https://github.com/gfx-rs/portability/blob/master/.travis.yml#L61) you will need to create an API key and commit it to the `.travis.yml` file. I've checked "allow edits from maintainers" so you should be able to commit to this branch directly. You may want to reference the [Travis instructions](https://docs.travis-ci.com/user/deployment/releases/#authenticating-with-an-oauth-token) as well.
- [ ] Tag revisions
Previous versions (`v0.1` - `v0.4`) have not been tagged on the master branch, you will want to do so retroactively. Also, when releasing in the future, make sure to tag the commit before pushing. Alternatively, you can schedule a travis build manually after applying the tag retroactively.
420: Make Origin3d::{x,y,z} all have type u32 r=kvark a=fintelia
Fixes#419
424: swapchain creation: check if selected present mode is supported r=kvark a=Veykril
Implements a simple check as talked about in #350 to fallback to `FIFO` should the selected present mode not be available on the system.
Co-authored-by: Korijn van Golen <k.vangolen@clinicalgraphics.com>
Co-authored-by: Korijn van Golen <korijn@gmail.com>
Co-authored-by: Jonathan Behrens <fintelia@gmail.com>
Co-authored-by: Veykril <lukastw97@gmail.com>
