Keep unmuted volume values if volume muted

If a volume control was muted, the hidden 'unmute volume' value was not
saved to the configuration, meaning that if you exit while muted then
restart, it would unmute to 100% each time, causing annoyance for some
users.
Merge branch 'master' of https://github.com/jp9000/OBS into obsvce
Stats. "Manual" keyframes.
Merge branch 'obsvce' of https://github.com/janeuner/OBS into obsvce

Conflicts:
	ObsVCE/src/ObsVCE.cpp
Don't force IDR manually with CBR.
Hack MFT into this. Disabled hw encoder sync fix for now.
Add ObsVCEMFT.
Delay first frame, maybe fixes hang when ending streaming.
Don't free library. Encoding settings calls InitVCEEncoder, duh.
Fixes and checks for MF. DrainOutput.