Add content categories for states & RSS feeds
Add feedzirra gem for consuming RSS feeds.
One less query for retrieving hierarchy
Add Hashie gem
Create RSS feed version model
Add methods for getting pages by category and creating/updating a feed entry
Create RSS feed class

- Add methods for retrieving pages categorized as
  RSS feeds, importing feed entries, checking for
  update content, and tracking feed etag/last 
  modified date
- Tests or it didn't happen