Merge pull request #2 from dwtj/master

Added frame_data(), receive_message(), and fixed heartbeat() and ping()
Merge pull request #4 from dwtj/master

Implemented `aux.py` and some of the simpler command handlers.
Made error happen if incorrect number of data bytes are received
Changed docs slightly
Added some partially implemented functions in oi and servo
Merge David Alex changes???
Merge branch 'master' of git://github.com/aore/mars-rover into aore-master

Conflicts:
	control/comm.py
	control/servo.py