ZynAddSubFX has gained some new developer power so development has been
going on well for quite a while now in their Git repo. It's time for
the first big resync so future changes can be integrated easily.
While regular instruments were excluded from processing when muted
this did not happen for InstrumentPlayHandle-based instruments. Muting
for exampling tracks with VSTi's inside did not decrease CPU usage.
Checking whether related InstrumentTrack is muted before calling
Instrument::play() fixes this issue.
Closes#2857426.
Added a new GUI-less mode to ZynAddSubFX instrument plugin which allows
to let ZynAddSubFX audio processing happen within LMMS, giving a much
better realtime behaviour.
As soon as showing up the GUI settings of GUI-less ZynAddSubFX instance
are saved and a traditional RemoteZynAddSubFx process is being launched
and the settings are applied there.