NAME:
  sortpair
 PURPOSE:   (one line only)
  Sort a pair of vectors by the first and return a sorted copy
 DESCRIPTION:
 CATEGORY:
  Miscellaneous
 CALLING SEQUENCE:
  sortpair,vec1,vec2,sorted1,sorted2
 INPUTS:
  vec1 - First input vector (numbers, not strings)
  vec2 - Second input vector (numbers, not strings)
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
 OUTPUTS:
  sorted1 - sorted copy of vec1, sorted by vec1
  sorted2 - sorted copy of vec2, sorted by vec1
 KEYWORD OUTPUT PARAMETERS:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
  Written by Marc W. Buie, Southwest Research Institute, 2019/06/04