Implement basic i18n support

Internationalized all templates, python sources, and javascript sources. The exception to this are the log messages, which are not translated.  There is no language switcher yet, but the messages files are loaded into the locale/ directory of the project.

I updated the "ci" branch as well, to compile messages if they are found in the locale/ directory.

The staging server will need to be updated with `apt-get install gettext` and `pip install django-rosetta` when this is pulled.