Studio: Resolves Notifications UI showing in IE9 + CSS Split

This Studio work does the following:

* provides a fallback to displaying "is-shown" notification UI elements for IE9. 
* splits our application-centric CSS (formally stye-app.scss/css) into two css files to resolve Studio's styling going over the IE 9 rule/selector CSS limits (http://blogs.msdn.com/b/ieinternals/archive/2011/05/14/10164546.aspx).

If you want to test the number of rules being used, crack open your console and run this gist in a view - https://gist.github.com/psebborn/1885511