Make graph augmentation a TracPM method.  Refs #9648.
Make graph augmentation a TracPM method.  Refs #9648.

Need to do this before trying to reschedule in ticket change listener.

git-svn-id: 2159781fc7c14c6bdd1f7e265daf7a25099c31e7@12746 7322e99d-02ea-0310-aa39-e9a107903beb

trac-hacks/trac-jsGantt,trac-hacks/trac-jsGantt,trac-hacks/trac-jsGantt