Initial work on some backwards-incompatible fixes to automation, mostly
around the bug where re-ordering plugins within a track does not move
their automation.  (plus the new system just scales better anyway...)
Still re-working automation...
Mostly have the new, fixed automation working again...  Still various tuning
to do, but automation is now somewhere between idiot-proof and future-proof.
I think this mostly fixes automation...  Still need to test some other
aspects of it, but the base functionality is back...