It was only processing a single event per call. The docs say
> Fetches all the events that are pending, calls the callback function
> for each of them, and returns.
which suggests that was incorrect.
All platforms should now receive events in the following order:
1. KeyboardInput(ElementState::Pressed, ..)
2. ReceivedCharacter
3. KeyboardInput(ElementState::Released, ..)
cc https://github.com/tomaka/glutin/issues/878
This expands input events to represent sub-pixel mouse positions, devices responsible for generating events, and raw
device-oriented events. The X11 back end is refactored to make full use of the new expressiveness. Other backends have
had new functionality minimally stubbed out, save for the macos backend which already supports sub-pixel mouse
positions.
