Refactor Events for use on National Day of Civic Hacking

Refactor various event-related platform features to prepare for the [National Day of Civic Hacking](http://hackforchange.org/events/national-day-of-civic-hacking-in-nyc).

Includes fix for #208: Update Upcoming Events Sidebar on Dashboard
![codemontage](https://cloud.githubusercontent.com/assets/226228/2980170/2c4739fe-dbe3-11e3-8b1a-f33a66e099eb.png)