Updated HtmlCleaner to 2.10 (see WOOKIE-431). Thanks to Jawwad Farooq for the bug report and testing this out.

git-svn-id: https://svn.apache.org/repos/asf/wookie/branches/wookie-1.0.x@1641345 13f79535-47bb-0310-9956-ffa450edef68