* clutter/clutter-behaviour-path.h:
* clutter/clutter-behaviour-path.c: Add a "knot-reached" signal,
which is emitted when the path reaches a node in the nodes list;
flesh out the documentation a bit; sync the parameters names
so that gtk-doc doesn't complain about missing stuff.
* clutter/clutter-behaviour.h:
* clutter/clutter-behaviour.c: Add the alpha value to the
ClutterBehaviour::alpha_notify vfunc, so you don't have to
get the value from the alpha inside the behaviour implementations;
add more documentation.
* clutter/clutter-alpha.c: Flesh out the description.
* clutter/clutter-actor.h: Update the header.
* clutter/clutter-behaviour-opacity.c:
* clutter/clutter-behaviour-scale.c: Update docs.
