"Hit Da Pavement," or Add footer.

Pivotal Tracker story 77658580.

Still TODO:
* [ ] Add [Code for America logo](http://www.codeforamerica.org/logos/) per branding guidelines.
* [ ] Add footer nav once [about/help/etc. pages exist](https://www.pivotaltracker.com/story/show/77672644).
* [ ] Update copyright to link to license once we [decide on one](https://www.pivotaltracker.com/story/show/77930646).

Known technical debt:
* [ ] Write functional tests.
* [ ] DRY #navigation and footer CSS.