Fix IE Touch pointer events passing through to the map

Pointer events in IE Touch would trigger on the map even when not started on the map. For example, if you had a dialog box on top of the map and dragged inside the map, the map would move. I believe this is because the handler never gets added to the obj[eventsKey] map. I noticed in the corresponding _off function below that the logic reaches there because of the multiple if/else statements. So I modified the _on even to match and it seems to fix the problem.

This would only seem to be a problem in IE Touch via the Metro interface. You can reproduce the bug by starting that and either using your finger or a mouse to drag on an element above the map to see the issue.