genercallback

   GENERCALLBACK - Generic callback function for user interfaces

   Attempts to call a function with the same name as the 'Tag' field in the
   figure handle with the callback object as the argument.

   Example:  Suppose there is a button pressed in Figure 1, and the 'Tag'
   field of Figure 1 is 'myFunnyPanel'.  Then, the generic callback calls
   the function 'myFunnyPanel(gcbo)';