Adding a basic partial API; Added file-based caching; Refactored templates. 

This pull request adds in the partial API (delivering sections and paragraphs without the chrome). This pull request makes all this work for regulation text. 

In general, it accomplishes quite a few things: 

1. Adds file-based caching (in development) to make the application faster. The appropriate settings have been added to dev.py. I don't know what those settings will look like in production. 

(You might want to turn off the cache if you're working with changes to the templates, or use a unique URL by appending ?<random_string>)

2. I've introduced a base.html that separates out all the page header and analytics stuff. This will make it easier to introduce new pages. 

3. simpler.html has been replaced with base.html + eregs_with_chrome.html and regulation-content.html. simpler.html was simply not a meaningful name. Splitting up the templates this way allows for the /partial API to work. 

4. I've added a run_server.sh script that let's you run the Django server.