Move stuff around in a coordinate system
Create a Rover specifying initial position and cardinal direction ('N', 'E, 'S', 'W') and optionally the size of the coordinate system. 100x100 is default.
Send a command by calling the Move method which takes a string.
Valid instructions are 'F' for forward, 'B' for backward, 'R' for right hand turn, and 'L' for left hand turn.
Invalid instructions and directions will be ignored silently.