Modified Phase B Smart Code + more

- Small change in RobotController.h (changed FORWARD_SPEED)
- Added new UnitTest (DriveStraightUnitTest)
- Added new UnitTest (DriveStraightUnitTest)

- Removed all IR logic from Smart Code for now
- Added drive straight PID code
- Added stop PID code (keeps the robot stopped even if someone pushes
it.
- Added comments for functions