[x] jump to bootloader failsafe mode
[x] basic LED control
[x] pulse-width modulation for LEDs
[x] USB CDC control and configuration
[x] USB CDC bulk transfer
[x] scaffolding for json parsing
[x] ambit command: boot
[-] ambit command: start
[-] ambit command: check
[-] ambit command: led
[ ] serial debug interface for logging/control
[ ] two-wire interface for component communication
[ ] display control