Remove keymap copy from GetKeyboardValuatorEvents, as
SwitchCoreKeyboard now takes care of this for us.
Remove unused variable and function prototype.
Update comments to be as informative as possible.
Move the keymap copying to event processing time (in
ProcessInputEvents), instead of being at event enqueuing time.
Break SetCore{Pointer,Keyboard} out into separate functions.
Change mieqEnqueue to take a device pointer, that asks for the
_original_ device associated with this event.