Another not-quite-there-but-better commit.

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

libs/ardour/buffer_set.cc

@@ -98,6 +98,7 @@ BufferSet::ensure_buffers(DataType type, size_t num_buffers, size_t buffer_capac
 {
 	assert(type != DataType::NIL);
 	assert(type < _buffers.size());
+	assert(buffer_capacity > 0);
 
 	if (num_buffers == 0)
 		return;