* clutter/sdl/clutter-backend-sdl.c:
(clutter_backend_sdl_dispose): Destroy the timer that we created...
(clutter_backend_sdl_init): ... here.
* clutter/sdl/clutter-backend-sdl.h: Add a GTimer for time-based
operations, like the event time.
* clutter/sdl/clutter-event-sdl.c:
(get_backend_time): Get the elapsed milliseconds for the SDL
backend.
(_clutter_events_init): Start the timer provided by the backend...
(_clutter_events_uninit): ... and the stop it.
(key_event_translate), (event_translate): Use the backend time
to fill out the time field of the event structures. This fixes
the motion notification throttling on the SDL backend.