Merge pull request #2 from dfedorth/master

Working Django implementation of usage app
Merge branch 'master' of github.com:UV-CDAT/usage
Added pydoc strings to app/views and app/models.
Removed login requirement for aggregate data. (total visits by country, etc)

/log/ now shows the stats without forcing you to log-in.
If a user is not logged-in, the detailed usage table is replaced by a message
prompting them to log-in. Also provides a link to /log/login/

/log/login/ is the new place to log-in from.
The authentication form now posts to /log/login/, and will redirect to
/log/ on successful authentication.