tune PID with pretty graphs

[robz]

We tuned the lm4f PID by eyeballing the data scrolling by and watching the response of the motors. It would be nice to have graphs depicting the PID response to commands, validating that our tuning is legit. Also to have pretty graphs to throw into our final paper.

[robz]

Pretty good guide on tuning pid: http://www.ece.drexel.edu/ctm/PID/PID.html