allow info window for identified features to be temporarily dragged

away from the identify location. Once a new feature is selected via the
previous/next arrow icons or a new identify is executed the window
bounces back to the proper identify location.

odd that the comparison below shows the whole file as changed. that was not the case when it was committed. The change is pretty minimal a `draggable` property to optionally enable the behavior and the `setupDraggable` method.