Change compass heading

We are going to consider the front of the orientation sensor to be the
short face opposite of the face with the reset button and the USB
connector since this is the face directed towards the front of Xandon's
robot.

These updates cause the following readings:
      0 degrees: The robot is facing north.
     90 degrees: The robot is facing east.
    -90 degrees: The robot is facing west.
 +/-180 degrees: The robot is facing south.