Add submodule for polar-control

WIP: Try to implement polar control with external encoder feedback. More work is needed.

Reduce PWM noise, simpler speed decoding, clean dependencies

Convert joystick to python3, crash on disconnect, Ui server listens on all interfaces

Set permissions in udev rule

Rename usb_controller.py

Rename dsPIC

Don't cut in the middle of dropped lines

Finally traced the CDC corruption back to XC16-781 bug

Comment CDC test

Little fixes

Change app_led_usb_status, stop motors on USB disconnect

Add remote procedures

Add tabs

Add bootstrap