Responsive implementation

*Do not merge*

Opening this request, but needs to be tested with new #327 code. I'm unable to do that at this time without a local instance of that app…

This is all changes to SCSS based upon the HTML of the current 18f.foia.us

The biggest change is that it adds a mobile, (unused) tablet, and desktop view. The desktop view is using a 12 column grid, while previously we were using 7 columns and shifting by 1.5. Mobile moves down to a 4 column grid. This had no ramifications with the current codebase, but conflicts may be present with #327