Features:
- 6 output channels
- Master BPM
- Separate divider or multiplier per chennel (from /32 to x24)

TODO:
- Add min and max values
- External clock
- Switch to U8G2 for screen
- Save state to EEPROM when stopped
- swing
- long-press encoder for settings (input mode, pulse length)
- analogue input for modulations

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