Basic National Day of Civic Hacking landing page

Improve Event pages display logic to include logo, description (with HTML), and RSVP button.

First event using new logic:
![national_day_of_civic_hacking_nyc](https://cloud.githubusercontent.com/assets/226228/2988302/52ec94da-dc58-11e3-8e7f-f35be2d6a7bd.png)