HUE-33. Protovision version has bug wherein mark events do not have their index properly set (IssueCreated)

This effects any hue app which uses protovis graphs and requires access to the mark index in event handlers.

ext/thirdparty/js/protovis/protovis-d3.2.js

@@ -8063,6 +8063,8 @@ pv.Mark.prototype.context = function(scene, index, f) {
   }
 
   /* Context switch, invoke the function, then switch back. */
+  clear(oscene, oindex);
+  apply(scene, index);
   try {
     f.apply(this, stack);
   } finally {