* Fixed CR r48837. Although using ids[]=x in the query string is wrong and broken...

* Fixed CR r48837. Although using ids[]=x in the query string is wrong and broken, ids[x]=1 works just fine and is a convenient interface.
* Fixed CR r49408: removed JS dependency for multiple revision delete/undelete. Using <button type=submit> we can submit the parameter "action=revisiondelete". The custom action is then distributed to Special:Revisiondelete, which can understand this kind of entry point with only minor changes.
* Also used <button type=submit> to avoid submitting the htmldiff button caption back to the server
* Show the same buttons at the top and bottom of the history page, refactored duplicated code