Overview document now contains references section

in response to dan's request for references in the overview document, 
the editors draft at the usual place -
http://www.ksl.stanford.edu/people/dlm/webont/OWLOverview.htm -
now contains a references sections.  (the appropriate other changes have 
happened too like updating the change log).

for completeness, the document is also attached here.

This is the last request that I am aware of to the overview document.

Deborah