test: Remove short option and fail on invalid options

Signed-off-by: Jonas Ådahl <jadahl@gmail.com>
udev: Drop unused seat_name in struct udev_seat

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Add libinput_event_get_context()

Add a function to retrieve the libinput context from any event.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>