This keeps track of whether surfaces received a key press event and
will only send a key release event if the pressed event was sent. This
also requires changing the keycodes that are sent via wl_keyboard_enter
to only include those that were previously sent. This makes it so
surfaces do not receive key release events for keys that they never
received a key press for and makes it so switching focus doesn't leak
keycodes that were consumed by bindings.
384afc5cb5