Added targets for LineFollower.

Added targets so that building and downloading to the brick were
separate steps to allow previously compiled code to be downloaded
quickly.
Cleaned up some variable names.

Made the code more concise.
Added Zeigler-Nichols calculator

Added a Python file to calculate the PID constants from the critical
gain, oscillation time, and loop time.
Adjusted flag order.

It seemed that the -q flag to nbc was being ignored. Made it the
first flag to test if that would do quiet compilation. Didn't work.
Line follower modifications.

Added ability to tweak k_p during run. Upped target power to 75%.
Removed code which logged to the NXT screen.
Merge branch 'master' of github.com:jbromley/Mindstorms