Changes functionality of Catapult::ReleaseHold()

Catapult::ReleaseHold() has been changed to move the motor until it hits
the limit switch. Also, Catapult::Hold has been removed because the
holding mechanism resets automatically.

A function called Intake::GetBallSensor() has been created which returns
the value of the ball sensor limit switch

The values of PRESSED and RELEASED have been switched because that is
the way we will wire our limit switched

Bijan and Sam