m3pi_ros

start at a unittest for the robot's motion controller. Unfortunately, does not seem to wait long enough for motion to complete before doing comparison

fixing dead-band in linear velocity for controller - now actually gets to toal

added code to publish world frame based on markers strewn on ground

adding stupid-simple proportional controller

removing obsolete test script (I need to figure out how to automate ROS tests), and adding node that actually communicates with the robot, as well as launch file for it