NAME:
  hstloadhdr
 PURPOSE: 
  Extract information from HST data headers and put in hstast.header database.
 DESCRIPTION:
  Reads all xxxxxx_flc.fits.gz files and creates rows in the header table.
 CATEGORY:
  Database
 CALLING SEQUENCE:
  hstloadhdr
 INPUTS:
 OPTIONAL INPUT PARAMETERS:
 OUTPUT:
 KEYWORD INPUT PARAMETERS:
   PATH        - Path to data directory,
                   default is '/net/amber/raid1/buie/hst/12897/'
   OVERWRITE   - Will overwrite existing files and data base entries if
                 specified, otherwise it will issue warnings on duplicates and
                 leave the existing entries unchanged. If two data base entries
                 are found for something to be added, it is considered a fatal
                 error and the loadhdr will terminate  unconditionally.
            
 COMMON BLOCKS:
 SIDE EFFECTS:
  Creates entries in the hstast.header table for each _flc.fits.gz file 
    encountered.
 RESTRICTIONS:
 CONFIGURATION: (optional, overrides xtrack.in)
   File: config.ini
   [global]
     subdir   - naem of sub-directory  added to base path to find data
   [ddir]   - section to list potential root directories to find data
     XXX - 
       XXX is a unique string (eg., D01)
        is a directory path
       for additional details see getddir.pro
 COMMON BLOCKS:
 PROCEDURE:
 MODIFICATION HISTORY:
  2012/07/02, Written by Marc W. Buie, Southwest Research Institute, cloned
                  from loadhdr.pro from the HST Cycle 17 project.
  2014/07/01, MWB, cloned for the NH search, program 13633.
  2016/07/15, MWB, added PROPID keyword
  2018/01/03, MWB, removed PROPID, now doesn't care what propid is.
  2020/06/22, MWB, generalized to hstast database and can be used for
                    all data, regardless of program