Sexy Scroll Bars

Common Sexy Scroll Bars (cross-UI).

The exact styling we can agree on and tweak.   Demonstration: http://jsfiddle.net/9vPys/1/

This change also introduces the concept of having common resources that can be shared between UIs.  Having common style sheets is probably going to be key to having a nice consistent look to the UI as a whole, and could help take out some of the effort in developing a new UI.