Feat/MIDI to audio

[harveysanders]

• Playing MIDI notes received from WebSocket over system audio
  • Caveats:
  • Playing chords panics!
  • MIDI rendered to float32 buffer with meltysynth
  • Buffers are sent to a mixer and played through system audio with beep!

• Virtual keyboard sends MIDI notes over socket

  • Hit [tab] to focus piano (no visual focus indication yet, other than chat will lose focus)

  • 

  • no visual indication yet

  • keybindings start at middle C and mimic real keyboard fingering

  • Velocity hardcoded to 127

  • Note duration hardcoded to 2 secs (including decay)

  • Loosely based on Garage Band's Musical Typing layout

TODO:

• [ ] Clean up API
• [ ] Better tests
• [ ] Handle note on/ off duration
• [x] Play multiple notes at once