DELGAUGE expression
    
   Synopsis:
      Deletes a 'main' window gauge
    
   Notes:
      Deletes a gauge that was added to the 'main' window with an ADDGAUGE or
         ADDCONGAUGE statement.
      The expression is the gauge's unique number. If the gauge doesn't exist,
         the DELGAUGE statement is ignored, but the number isn't an integer, 0 
         or above, you'll see an error message.

   Examples:
      DELGAUGE 1
