Add gobject-introspection annotations

Add annotations such as (transfer-none) (out) (element-type ClutterActor),
and so forth to the doc comments as appropriate.

The annotations added here are a combination of the annotations previously
in gir-repository for Clutter and annotations found in a review of all
return values with that were being parsed with a transfer of "full".

http://bugzilla.openedhand.com/show_bug.cgi?id=1452

Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>

clutter/clutter-behaviour-path.c

@@ -426,7 +426,7 @@ clutter_behaviour_path_set_path (ClutterBehaviourPath *pathb,
  *
  * Get the current path of the behaviour
  *
- * Return value: the path
+ * Return value: (transfer none): the path
  *
  * Since: 1.0
  */