NAME:
  occshowgrid
 PURPOSE:   (one line only)
  Show a grid of postage stamp images from an occultation dataset
 DESCRIPTION:
 CATEGORY:
  Occultations
 CALLING SEQUENCE:
  occshowgrid,team,nx,ny,dw
 INPUTS:
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
  HISIG - sigma level for upper stretch threshold (low is -3 sigma),
             (default = 5)
  ACTUAL - Flag, if set, use the D&R times (from chords.dat) to establish
             the reference time, otherwise just used the prediction
             (from crosstrack.dat).
  WINDOW - direct graphics window to use for display (default=0)
  SAVEPNG - Flag, if set, causes the display to be saved to a .png file.
              The file name will be [team]_grid.png.
 OUTPUTS:
 KEYWORD OUTPUT PARAMETERS:
 CONFIGURATION:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
  Written by Marc W. Buie, Southwest Research Institute, 2020/09/23