Elbow Mod Update

Since the last update I have fixed numerous bugs the navigation errors where due to a damaged encored disc and the arm jitter was due to mismatched names in the Joint state publisher. one of the requirement for ROS MoveIt is a follow joint action server this now works I was ready to start using MoveIt then the elbow worm broke again, the printer not working at this time so I incorporated the elbow mod into the robot.The original idea was to use a MXL belt but the weight and acceleration  cause the belt to slip, after a change to #25 chain and sprocket to operation was better. One side affect of this mod is the arm can droop down which on power on causes a sudden jerk as the arm moves to start position. A simple adjustment to the start position and to place the arm into the tuck position for driving will be required, maybe a spring to hold the weight   will also help.