NAME:
  mysqlsub
 PURPOSE:   (one line only)
  Recursive string substitution from mySQL doc table for building documentation
 DESCRIPTION:
 CATEGORY:
  Database
 CALLING SEQUENCE:
  mysqlsub,lun,instr,outstr
 INPUTS:
   lun   - The logical unit of the pipe (opened by openmysql).
   instr - String (scalar or vector) to be scanned.
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
 OUTPUTS:
   outstr - Copy of instr where all occurrences of <> have been
              replaced by the text contained in the database for FIELD
 KEYWORD OUTPUT PARAMETERS:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
   2005/01/20, Written by Marc W. Buie, Lowell Observatory