Add VCV modular synth support

[oubiwann]

VCV is a free, open source modular synthesis framework (Eurorack emulator):

• https://vcvrack.com/
• https://vcvrack.com/manual/
• https://library.vcvrack.com/
• http://www.studiobrootle.com/best-vcv-rack-modules/

Specific support: MIDI control of the synth. See the MIDI plugins for more details:

• https://library.vcvrack.com/?query=&brand=VCV&tag=MIDI&license=free

[oubiwann]

I think I want to put this in the newer, lighter-weight MIDI-only project: https://github.com/ut-proj/undermidi ...

[oubiwann]

Gonna close this one now.