Changes from Limor's upstream x0xb0x firmware by Chairman Meow

1.03

- Fix off-by-one-note bug in MIDI PLAY mode
- Add LEDs to MIDI PLAY mode
- Add LEDs to KEYBOARD mode
- Fix off-by-one MIDI channel storage in MIDI PLAY mode
- Add copy / save-as to PATTERN EDIT mode
- Default empty pattern to 16 notes, note C2
- Fix listening-on-every-channel MIDI PLAY bug