Making GtkAction 1-1 with GtkActionGroup

[Jody Goldberg <jody gnome org>]

http://bugzilla.gnome.org/show_bug.cgi?id=120648

Operating on ActionGroups rather than individual actions seems
conceptually simpler if we constrain a GtkAction to belong to at
most one group.  This would allow

1) The ability to change the sensitivity of an entire group at once
   without losing the state of individual elements as libbobonboui
   did.

2) It woul also provide a convenient place to do some signalling for
   large numbers of actions.  As an example a hook to do/check
   the same thing before every action would be useful in some cases.

Can anyone see an instance where this would be too strong a
requirement ?