* clutter/cogl/cogl.h: Update cogl_clip_set() to accept the
clip components as ClutterFixed values
* clutter/cogl/gl/cogl.c (cogl_clip_set): Update the GL implementation
of cogl_clip_set()
* clutter/cogl/gles/cogl.c:
(cogl_rectangle_internal): Provide an internal, inlined rectangle
drawing function using fixed point values, to be shared by
cogl_clip_set() and cogl_rectangle()
(cogl_clip_set), (cogl_rectangle): Update the GLES implementation
of cogl_clip_set() and cogl_rectangle() to use the new internal
rectangle drawing function
* clutter/clutter-actor.c: Make the clip an array of ClutterUnit
values instead of pixel-based; this allows higher precision and
device independence
(_clutter_actor_apply_modelview_transform): Pass the clip
components converting from units to fixed point values, using
the new cogl_clip_set() signature
(clutter_actor_get_property), (clutter_actor_set_clip),
(clutter_actor_get_clip): Update the accessors of the clip
property