NAME:
  rdoblist
 PURPOSE:
  Read a object list from a file.
 DESCRIPTION:

 CATEGORY:
  Astrometry
 CALLING SEQUENCE:
  rdoblist,file,nobj,filelist,dt,offset,pos,flags,idstr,nfiles
 INPUTS:
  file - String of file name to be read.
 OPTIONAL INPUT PARAMETERS:

 KEYWORD INPUT PARAMETERS:

 OUTPUTS:
  nobj     - number of objects in list.
  filelist - string array of file names for this object list.
  dt       - Array of time offsets with nfiles-1 elements.  The values are the
                time offset from the first frame in hours.
  offset   - 2*(nfiles-1) element vector [x,y offset (B-A), x,y offset (C-A), ...]
  pos      - [2*nfiles,nobj] element vector, each row is set of positions [x1,y1,x2,y2,x3,y3]
  flags    - nobj element vector of flags either ?, y, or n.
  idstr    - String array of description info for each measurement.
  nfiles   - Number of files in linked set of images for this field.

 KEYWORD OUTPUT PARAMETERS:
  VERSION  - The version id string for the file that was read.

 COMMON BLOCKS:

 SIDE EFFECTS:

 RESTRICTIONS:

 PROCEDURE:

 MODIFICATION HISTORY:
  1998/10/6, Written by Marc W. Buie, Lowell Observatory
  1998/11/2, MWB, generalized to handle other than frame triplets
  1999/2/19, MWB, added dt and version arguments.
  2000/11/9, MWB, removed Str_sep call.