[FIX] articles: Use the html purifier to sanitize html article content, instead of the default one (which messes up some plugin params). Should help with wish4796, thanks Xavi

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@48131 b456876b-0849-0410-b77d-98878d47e9d5