Add support for encodeing and decoding raw binary MIDI messages

[oubiwann]

There's a lot to cover in the MIDI specs, so we'll keep it simple at first.

Note that the impetus for this feature is the experimental epic issue+branch in the midiserver project where the Erlang NIF from Sonic Pi is being used to send bytes directly to MIDI devices

Tasks:

• Create new module, midibin
• Create midibin:encode function
  • support aftertouch/1
  • support note_off/1
  • support note_on/2
  • support pitchbend/1
  • support cc/2
  • support program_change/1
  • support reset/2
  • support sys_ex/1
  • support channel/1
  • support the non-standard (midilib-only):
    • batch/1 and batch/2
    • support bank_select_msb/1
    • support bank_select_lsb/1
• Create midibin:decode function
  • support aftertouch/1
  • support note_off/1
  • support note_on/2
  • support pitchbend/1
  • support cc/2
  • support program_change/1
  • support reset/2
  • support sys_ex/1
  • support channel/1
  • support the non-standard (midilib-only):
    • batch/1 and batch/2
    • support bank_select_msb/1
    • support bank_select_lsb/1

[oubiwann]

Calling it done.