First push of vertical nav feature

- Adds 'you are here' feature to homepage, a la #46 

![screenshot 2014-10-16 15 51 41](https://cloud.githubusercontent.com/assets/4827522/4671885/1bb1d02c-5587-11e4-8e0f-411dad057849.png)

Also includes tooltips describing each section
![screenshot 2014-10-16 15 51 57](https://cloud.githubusercontent.com/assets/4827522/4671890/284a864e-5587-11e4-8c39-145f57e895b4.png)