twDelMSpot( nSpotNo, aHotSpot, nNxtHandl )
 ----------------------------------------------------------------------------
     Remove a mouse Hot Spot created  with twAddMSpot().

       Arguments:

     nSpotNo   - 'N' which is the handle of the region to remove.

     aHotSpot  - 'A' The array of hot spots.

     nNxtHandl - 'N  The next free spot in the array of hot spots

       Return:

     The next available spot.

       Example:

     FUNCTION RemHotSpot( nSpotNo )
     nNxtHandl := twDelMSpot( nSpotNo, aMouseSpot, nNxtHandl )
     RETURN NIL