* Don't use UNIX_BACKEND in Window2::new
* Move get_available_monitors and get_primary_monitor to EventsLoop
* Remove UNIX_BACKEND
* Restore choosing the Linux backend
* Return a XNotSupported for new_x11()
* Fix fullscreen example
This removes the need for the EventsLoop::interrupt method by inroducing
a ControlFlow type. This new type is to be returned by the user's
callback and indicates whether the `EventsLoop` should continue waiting
for events or break from the loop.
Only the wayland, x11 and api_transition backends have been updated so
far, and only the wayland backend has actually been tested.
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.
