r191@gandalf: fugalh | 2006-07-24 19:50:10 -0600

 r191@gandalf:  fugalh | 2006-07-24 19:50:10 -0600
 All the obvious MementoCommand grunt work. Now there's some
 add_undo/add_redo_no_execute sprinkled around where one is separated from the
 other (e.g. in different callbacks) or perhaps even where there's only an undo
 and no redo. Also some sigc-based undo/redo pairs that probably need their own
 Command class.

git-svn-id: svn://localhost/ardour2/branches/undo@692 d708f5d6-7413-0410-9779-e7cbd77b26cf