- GUI is missing a display for the actual state of the machine
   (tracking, positioning, stopping, stopped, etc.)

 - Implement the ZdAz Positioning in a more proper way (using some fOffset)

 - Add a MCallback interface to be able to get a notice if the
   shaftencoder position changed (recalc fOffset, fTracking Error
   as often as possible)
   
 - Check why it crashes if you exit the program while 'going home'