Added LogPOT command which will log the potentiometer voltage, as well
as the angle computed from the voltage.
The command has been mapped to the A button on the driver joystick
kDegreesPerVolt has been calculated, and the zero position of the
potentiometer has also been calculated, and these values are used to
calculate an absolute angle from the potentiometer voltage.

Steering for drive has been switched back to the right stick of the
driver joystick.
Merge branch 'master' of https://github.com/NorthernForce/NorthernForce-Robot-2013