[RIFRAF] ACTION-175 new rifraf ontology using imports

Dear Rifers,

As Chris requested on the last telecon I have redone the RIFRAF
ontology using imports.  I have attached the Owl and protégé project
files.

If you look at the Metadata tab in Protégé you will see what I did.
The new integrated ontology has URI http://www.w3.org/2007/04/rifraf.
It imports the initial RIFRAF ontology produced by Sandro and Axel
which has URI http://www.w3.org/2006/10/rifraf#.  It also imports
another ontology which represents the portion that I contributed to
handle semantic discriminators, with URI
http://www.w3.org/2007/04/semDisc.  I gave the latter the prefix "sem,"
i.e., all class names C (etc), belonging to that ontology will appear
as sem:C.  

I did not come up with a prefix for the part of the RIFRAF ontology
worked on by Sandro and Axel.  Protégé uses "p2" as a default prefix
for that ontology.  

The only class these two pieces share in common is p2:Language.  I have
introduced some subclasses under that class.

Enjoy,

Allen

=======================================================
Dr. Allen Ginsberg,       Lead Engineer
The MITRE Corporation     Information Semantics Group
Voice: 703-983-1604       7515 Colshire Drive, M/S H305 
Fax:   703-983-1379       McLean, VA 22102-7508, USA