Expose models to the admin interface

There are some pluralization bugs; hopefully it doesn't matter.
Appease the style gods

* Remove trailing whitespace in a few places
* Fix a place where PEP8 whined about the indentation of comments
Extract base template from home.html

It's mostly the <head> tag.
Actually store votes

At this stage all votes are made by a default dummy team of one:
the superuser. This fails if the automatic Django prompt to create
a superuser is dismissed. Reminder: you can create one with:

  python manage.py flush
Plug in the Django authentication system

Require users log in before they vote

(N.B. Votes still belong to the first user in the database)
Fix miscealleaneous style issues

The main problem here is that LESS does not add different units
of measure meaningfully: 2px + 3em = 5px, not 66px.

Also change a few links to be more button-like.
Add about page

Short blurb about the site, linked to from all pages
Add a bunch of hints to the homepage

A hint is chosen randomly to be shown on the vote page.