Apply the mask to the given object setting all pixels
      within the mask to the mask value. The object must be
      a woolz grey-level object, the mask can be a domain object,
      polyline or boundary list which will be filled to make
      a domain. The mask is always the second object if read
      from the standard input
      Options are:
      -m#       the mask value - default 0
      -h       help - prints this usage message
      -v       verbose operation