Brought plugin automation into the fold of new automation system.
Fixed plugin automation, broke panner automation :] (pending Panner work).
Made AutomationController better at automatically following it's controller value (mimic what gain meter does).
Fixed some visible automation track bugs (but still broken WRT serialization).
git-svn-id: svn://localhost/ardour2/trunk@2092 d708f5d6-7413-0410-9779-e7cbd77b26cf