Add sponsorship page

:sparkles: Adds sponsorship opportunities page based on original prospectus gist. Also adds a blurb about sponsoring and a link to the sponsorship page on the homepage.

![screen shot 2014-02-19 at 7 52 42 am](https://f.cloud.github.com/assets/316507/2206576/d2ceb840-9964-11e3-8329-ce1ca4e199db.png)
![screen shot 2014-02-19 at 7 52 27 am](https://f.cloud.github.com/assets/316507/2206577/d4f8e03c-9964-11e3-8c36-74f287e6431b.png)