NAME:
  bildmask
 PURPOSE:
  Stack a set of bad pixel mask images into one master mask.
 DESCRIPTION:

 CATEGORY:
  CCD data processing
 CALLING SEQUENCE:
  bildmask,outfile
 INPUTS:

 OPTIONAL INPUT PARAMETERS:

 KEYWORD INPUT PARAMETERS:

 OUTPUTS:

 KEYWORD OUTPUT PARAMETERS:

 COMMON BLOCKS:

 SIDE EFFECTS:

 RESTRICTIONS:

 PROCEDURE:

 MODIFICATION HISTORY: