other stuff todo
  1. GL: mono/gray scale not handled right, should also have letters on cube
  2. Orient mode is not complete enough to ensure you have returned to the
   original state when in period 2 mode or both mode.  For example, left and
   right faces could now be adjacent.
  3. Fix drawing error in GL when period 2 and back is turning.
  4. Change speed in GL with Animation speed.
