* clutter/clutter-main.c (_clutter_id_to_color): When choosing a
pick color, set all but the most significant of the unused
bits. This should make make it more likely that the GL
implementation will round down to the right value.
* tests/test-pick.c: Test case for picking. It creates 192 actors
at known positions and stores their gids. It then calls
clutter_stage_get_actor_at_pos with each position to check that
the right gid is returned.
* tests/Makefile.am (noinst_PROGRAMS): Add test-pick
