Added Retrieval code

Started working on retrieval code.
Worked on retrieval

Fixed some retrieval stuff
Assigned buttons to operations

buttons for belts, secondary joystick y axis controls retrieval, added
ultrasonic to turn on a light at 36-72 inches, gear shifting with
solenoids
Fixed issues

moved gear shifting to chasis, cleaned up various code
Added direction class

Moved direction values into it's own class.
Merge pull request #12 from TrojanRobotics/Retrieval

Retrieval