Features:
- 6 output channels
- Master BPM
- Separate divider or multiplier per chennel (from /32 to x24)
- Per-channel random pulse skip (currently only 50/50 chance)
- 2 inputs for external modulation (assignable per channel)
- All channel settings and bpm are saved on play/pause and recalled on power up

TODO:
- different chance options for random
- design PCB
- external clock
- swing
- settings (input mode, pulse length)

Timer library available here
https://github.com/PaulStoffregen/FlexiTimer2

KiCad SSD1306 display component
https://github.com/pforrmi/KiCad-SSD1306-128x64