Methods in ShooterSubsystem need to be called periodically

[LeonardAbbas]

This is a problem because we can't control multiple parts of the shooter at the same time. (ie if we have 2 separate commands for controlling the arm and the flywheel, they can't be run at the same time because they both require the same subsystem)
This could be fixed by moving logic into the periodic() method of the subsystem.