Updates js versions.

index.html

     <script src="app.js?v=24"></script><!-- application logic -->
     <script src="chat.js?v=4"></script><!-- chat logic -->
     <script src="util.js?v=3"></script><!-- utility functions -->
-    <script src="etherpad.js?v=6"></script><!-- etherpad plugin -->
+    <script src="etherpad.js?v=7"></script><!-- etherpad plugin -->
     <script src="prezi.js?v=2"></script><!-- prezi plugin -->
     <script src="smileys.js?v=1"></script><!-- smiley images -->
     <script src="replacement.js?v=5"></script><!-- link and smiley replacement -->