Update to final YUI 2.8.0 release (r6) and add missing components needed by Tag Autocomplete feature.

git-svn-id: https://svn.apache.org/repos/asf/roller/trunk@1608218 13f79535-47bb-0310-9956-ffa450edef68
Remove unneeded YUI dragdrop reference.

git-svn-id: https://svn.apache.org/repos/asf/roller/trunk@1608219 13f79535-47bb-0310-9956-ffa450edef68