Support page skins & Break navigation on two levels on desktop

Here is what the nav looks like on desktop and when the page has a page skin:

![screen shot 2014-07-21 at 21 00 44](https://cloud.githubusercontent.com/assets/85783/3649419/2e29f28e-1112-11e4-83b0-89cc15566551.PNG)

![ ](http://gifs.joelglovier.com/teamwork/jump-rope-record.gif)