Joystick events

[LaylBongers]

The recommended method of getting joystick events on Windows, for devices that do not fall under the XInput API, is to use the raw input API (WM_INPUT). I saw that winit already does this for mouse & keyboard events, but not yet for joysticks.

Since I've got a need for this in my own project, I hope to soon give a shot at implementing this on Windows, but if anyone else who is more familiar with this API can implement it faster than I could, that would be appreciated.

[francesca64]

Funnily enough, I implemented both this and version-agnostic XInput support a while ago... https://github.com/francesca64/winit/tree/win-joy

I just never merged it, since I was concerned about breaking the API later on, and it's missing some special-casing for rumble/etc. I expected to iron out the design more by implementing joystick support on Linux and macOS, but never got around to it.

So, I guess I should rebase it and make a PR.

[Osspial]

@francesca64 I'd be up for taking over that PR, rebasing it against the event loop 2.0 code, and getting it ready to release on Windows, if you're okay with it.

[francesca64]

@Osspial absolutely! Thanks a bunch.