Language Selection

Fixes #144. This adds a language selection dropdown to the footer which allows the user to change their language which will result in changing the site content. This will also make it clear that #160 is not an issue.
It's funny, because I could have sworn that was one of the first things I checked, but you're right, the changes were somehow missing from the compressed output. I reran `manage.py compress` and restarted gunicorn again, and now the changes are showing up and working as expected. Thanks @mlavin!