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 have been
replaced by the text contained in the database for FIELD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