[Zope] HTMLDocument workaround for Zope 2.6

My recent upgrade to Zope 2.6.1 broke HTMLDocument 0.9(.1). http://www.zope.org/Members/sf/HTMLDocument/ It referenced InterfaceBase, something that has apparently disappeared. Digging only slightly deeper, I noticed that it wasn't even being used. The easy fix is to just comment out line 27 in HTMLDocument.py (from IHTMLDocument import IHTMLDocument). --kyler