ProjectDemo: Stop text controller from doing an automatic commit during undo

git-svn-id: http://svn.gna.org/svn/etoile/trunk/Etoile/Frameworks/CoreObject@10128 7b3f36aa-e6db-49c1-8b4c-66eac1997e64
COUndoTrack: supply commit metadata when committing in the implementation of -undo / -redo, so if COCommandSetCurrentVersionForBranch has to generate a new revision, it has sensible commit metadata. (unfortunately, the best I can come up with involves 'baking in' the localized description of the change being undone/redone)

git-svn-id: http://svn.gna.org/svn/etoile/trunk/Etoile/Frameworks/CoreObject@10129 7b3f36aa-e6db-49c1-8b4c-66eac1997e64