Added OneXboxTankDrive, OneXboxGTADrive, and OneXboxGTASim control scheme classes.
changed "controlConveyor()" to "controlConveyer()" to match spelling of the SingularityConveyer class.
eliminated the tank() and arcade() methods in the control scheme classes (and interface), replacing them with just one drive() method. This was necessary because which drive type is being used depends on the control scheme.