i Bug 560228 – Add "action-controller" property to GtkWidgetClass

i        Bug 560228 – Add "action-controller" property to GtkWidgetClass

        Rework the way actions and proxies interact, to make the
        interaction less ad hoc, more extensible, and better suited
        for support in GUI builders like glade.

        To be used as a proxy, a widget must now implement the
        GtkActivatable interface, and GtkActivatable implementations
        are responsible for syncing their appearance with the action
        and for activating the action.

        All the widgets that are commonly used as proxies implement
        GtkActivatable now.

        Patch by Tristan van Berkom.

        * gtk/gtkactivatable.[hc]: The GtkActivatable interface.

        * gtk/gtkbutton.c:
        * gtk/gtktogglebutton.c:
        * gtk/gtktoolitem.c:
        * gtk/gtktoolbutton.c:
        * gtk/gtktoggletoolbutton.c:
        * gtk/gtkmenuitem.c:
        * gtk/gtkcheckmenuitem.c:
        * gtk/gtkimagemenuitem.c:
        * gtk/gtkradiomenuitem.c:
        * gtk/gtkrecentchooserprivate.h:
        * gtk/gtkrecentchooser.c:
        * gtk/gtkrecentchooserdefault.c:
        * gtk/gtkrecentchoosermenu.c: Implement GtkActivatable.
        * gtk/gtkaction.[hc]: Move appearance synchronization to
        GtkActivatable implementations.

        * gtk/gtkradioaction.c:
        * gtk/gtkrecentaction.c:
        * gtk/gtktoggleaction.c:
        * gtk/gtkactiongroup.c: Adapt.

        * gtk/gtk.h: Include gtkactivatable.h
        * gtk/gtk.symbols: Add new functions

svn path=/trunk/; revision=22195