Add rplidar sample

This is the initial Processing sample that I wrote for Xandon to use
for testing and integrating the RoboPeak LIDAR into his robot.  It's
still a bit rough around the edges but good enough to kickstart
Xandon's work.

The code under the rplidar/firmware directory was code that I wrote for
an mbed to simulate the protocol spoken by an actual RPLIDAR so that I
could test my code when I didn't have an actual RPLIDAR at my house to
test with.
Add more documents

I have added two more PDFs:
* One for the Sparkfun Monster Motor Shield that I plan to use for
  initial testing on my 6WD Wild Thumper robot chassis.
* The other is for the VNH2SP30 motor driver chip used on the Monster
  Motor Shield.