Make whole list item styleable.

This change add's class name to the whole `li` element to allow more configurable styling like how my osx-skin does it for example:

![screen shot 2014-03-21 at 16 08 58](https://f.cloud.github.com/assets/21236/2488905/178acb26-b14e-11e3-8f74-ede959387a8a.png)