Added separate ZynAddSubFX repository as submodule
Initial integration of updated ZynAddSubFX
ZynAddSubFX: Use upstream icon file
VeSTige: adapt rename of MidiMaxKey constant
ZynAddSubFX: initialize IO engine after setting up synth instance
ZynAddSubFX: define PLUGINVERSION macro

Removes exit confirmation dialogs etc. in MasterUI.fl
RemoteZynAddSubFX: start/stop NIO system

Fixes crash when showing GUI of ZynAddSubFX.
ZynAddSubFX: update submodule reference
ZynAddSubFX: update submodule reference
ZynAddSubFX: update submodule reference
Merge remote-tracking branch 'origin/stable-0.4-zynaddsubfx-update'

Conflicts:
	plugins/zynaddsubfx/src/DSP/AnalogFilter.h
	plugins/zynaddsubfx/src/Effects/EffectLFO.h
	plugins/zynaddsubfx/src/Effects/Reverb.h
	plugins/zynaddsubfx/src/UI/EffUI.fl
	plugins/zynaddsubfx/src/UI/EffUI.h
	plugins/zynaddsubfx/src/UI/EnvelopeUI.fl
	plugins/zynaddsubfx/src/UI/EnvelopeUI.h
	plugins/zynaddsubfx/src/UI/FilterUI.fl
	plugins/zynaddsubfx/src/UI/FilterUI.h
	plugins/zynaddsubfx/src/UI/PartUI.cc
ZynAddSubFX: integrated latest version