Start microcontroller-side code for arms

[bsawka]

Just as the locomotion microcontroller accepts input and actuates the motors in HeadLocomotion.ino, we need a similar program to run on the arms Arduino. The program will be very similar to the final version of HeadLocomotion.ino - it should accept R2Protocol-encoded messages from the Jetson (probably consisting of an angular amount to move), actuate motors to the correct place using rotary encoder feedback, and be able to send update messages (again, with R2Protocol) to the Jetson.