Improvements for debug toolbar (#838)

Add panel to display used asset  bundles

Summary
![](http://cdn.joxi.ru/uploads/prod/2014/09/18/e03/92f/6770521df710911289940a73c1a5030630684d00.jpg)

Detail
![](http://cdn.joxi.ru/uploads/prod/2014/09/18/7d4/b2a/aec6db3da0caf1af87a9ff86ff86253b8b9d4ec4.jpg)