Add banks from RoTT

Source: https://github.com/OpenSourcedGames/Rise-of-the-Triad/tree/master/audiolib/PUBLIC/PM
Improve 256-color instrument allocation
replace screenshot
README.md: Sustaining versus releasing?
std::queue performance enhancements in USE_REVERB

Forward-ports d7208f9 ("std::deque performance enhancement")
Fix USE_REVERB code path for float samples
Don't add back average in SendStereoAudio
Don't start SDL audio if writing to PCM file
Make reverb switchable with command line switch
Fix writing audio to disk
Make reverb actually work again
Mention -noreverb in README.md