Merge pull request #20 from shawnbot/master

Fix the minimum education level values, and update README accordingly
Merge branch 'master' of github.com:kaitlin/hourglass
use unicodecsv instead of built-in csv module
don't add ?format=csv to export link href, per #21
made indent uniform, updated empty results
Merge branch 'master' of https://github.com/shawnbot/hourglass