Joint Position Waypoints Example Program

Simple example program showcasing simple point to point motions.
Should be simplest example to get the arm moving quickly and accurately.
Updates per review #20

Breaks out record and playback functions.
Eliminates button press callback race.
Logging, docstring cleanup.
Merge pull request #20 from RethinkRobotics/joint_position_waypoints_example

Joint Position Waypoints Example Program