ROS node used to communicate over serial.
This code was based mostly on the ROS serial comms node created by Dr. Rainer Hessemer (http://www.hessmer.org/blog/2010/11/21/sending-data-from-arduino-to-ros/)
Set up instructions can be found at http://bots.cs.mun.ca/robots/bu-pi-zu-name-negotiable/