Resolution of ISSUE-148 (topDataProperty) implemented

Hello,

I've just implemented the resolution of ISSUE-148 (topDataProperty); here are the diffs:

Syntax:
http://www.w3.org/2007/OWL/wiki/index.php?title=Syntax&diff=14560&oldid=14551

Direct Semantics (a minor update to the proof of Theorem 1 was needed):
http://www.w3.org/2007/OWL/wiki/index.php?title=Direct_Semantics&diff=14562&oldid=14032


I've also made one editorial change in the Syntax document: owl:topObjectProperty can now occur as a subproperty in
SubObjectPropertyOf axioms. There was no real need for this restriction. I made this change because, after I had added a set of
similar but different restrictions on owl:topDataProperty, the two restrictions struck me as rather convoluted and messy. To
simplify matters, I've simply removed the unnecessary restriction on owl:topObjectProperty.

Regards,

	Boris