Use CFAPI on /geeks page.

Started to use the CFAPI on the /geeks page. It grabs the current list of Brigades from the API and shows the list on the page behind a faded toggle.

Uses vanilla javascript and fails gracefully with out js.

Tested great on Chrome, Firefox, Safari, and Chrome iOS.

View at http://jekit.codeforamerica.org/codeforamerica/codeforamerica.org/geeks-js/geeks/