/about page changes, and a new /developer page

This pull request does two things: 

1. Add more content to the /about page
2. Introduce a /developers page.

I've made the /about page where we put a little bit of help for the user. The description of features does that, I think in letting users know what is possible. This is sort of what I'm going for: http://www.consumerfinance.gov/eregulations/about. That's also a good example of what the /about page could look like with some design help. On eRegulations the about page was a very useful thing to direct people towards, because it described the tool, and what features existed. 

I've introduced a /developers page that links to the Github repositories, the API documentation etc. 
In both cases, I consider the content a start, and we'll likely iterate on both many times.