button: replace deprecated ClutterContainer API
button: replace deprecated ClutterContainer API

Replace deprecated ClutterContainer API with new ClutterActor API.

clutter-project/mx,jonnylamb/mx,jonnylamb/mx,jonnylamb/mx,clutter-project/mx,pwithnall/mx,pwithnall/mx,pwithnall/mx,pwithnall/mx,clutter-project/mx,jonnylamb/mx,clutter-project/mx