Draggable input tiles

Please pay attention to: 
The updating of the data model based on tile dragging.  This includes:
1) Updating the order of inputs upon input tile dragging.
2) Ensuring text fields properly lose focus so ValueChangeEvents are fired, allowing the underlying data model (experiment) to be changed.

Please Note:
Due to a known bug in gwt 2.1, input tile dragging may cause the Google Chrome tab to crash in dev mode, so please test in Firefox.  Apparently it should work find in production mode.
Link to StackOverflow response: http://stackoverflow.com/a/10685140/1971245
Link to GWT issue: https://code.google.com/p/google-web-toolkit/issues/detail?id=5778#c65