[BLD/FLD] Updated

Recent updates by Michael and me include
splitting uniterms into atom and expr,
introducing external queries for builtins,
and incorporating the essence of Jos'
FLD presentation syntax:

http://www.w3.org/2005/rules/wiki/BLD
http://www.w3.org/2005/rules/wiki/FLD#EBNF_Grammar_for_the_Presentation_
Syntax_of_RIF-FLD

This update cycle is still in progress.

-- Harold