[Still in progress] create Terms of Service page and link

here's current inclusion
![image](https://f.cloud.github.com/assets/2665886/846263/0e1a276a-f409-11e2-93f1-e148dc2a3d4a.png)

still to do: 

- css review
- insertion of actual ToS content in the new view I've created `pages/terms_of_service.html.haml`
- styling of the ToS text