* clutter/clutter-group.c:
* clutter/clutter-group.h: Add the clutter_group_add() convenience
function; it's now "undeprecated" and implemented as a macro
* clutter/clutter-stage.h: Add clutter_stage_add() as a convenience
macro
* clutter/cogl/cogl.h: Include just the needed headers instead
of the whole clutter.h; this avoids rebuild cogl when not needed
e3ebfdb14b