(clutter_frame_source_add_full): Add gtk-doc and rename the
'function' parameter to 'func'.
* clutter/clutter-frame-source.h: Rename the 'function' parameters
to 'func'.
* clutter/Makefile.am (source_h): Make clutter-frame-source.h a
public header.
* clutter/clutter-main.c (clutter_threads_add_frame_source_full):
Improve gtk-doc
* doc/reference/clutter/clutter-sections.txt: Added
clutter_threads_add_frame_source,
clutter_threads_add_frame_source_full,
clutter_frame_source_add and clutter_frame_source_add_full.
