ProjectDemo: use persistent root UUID as the default undo stack name, so undo stacks persist across app launches
ProjectDemo: use persistent root UUID as the default undo stack name, so undo stacks persist across app launches

git-svn-id: 3f5c6d78ff0be2386f5eccc3304aa879623f5ca8@10207 7b3f36aa-e6db-49c1-8b4c-66eac1997e64

etoile/CoreObject,chris-armstrong/CoreObject,etoile/CoreObject,chris-armstrong/CoreObject,chris-armstrong/CoreObject,etoile/CoreObject,etoile/CoreObject,chris-armstrong/CoreObject