keeping Jeremy happy

In a continuing effort to keep Jeremy happy, I have added more special
cases to the mapping from the abstract syntax to RDF graphs.  This makes it
more likely to ``accidentally'' build OWL/DL ontologies when writing
XML/RDF.

I believe that the changes do not make any RDF graphs that were OWL/DL
ontologies no longer be OWL/DL ontologies.

The new version of the semantics document is available in the usual place.
It has a date of 30 December 2002, although there have been several
versions with that date available today. 

peter