Upgrade to Django 1.5

Everything looks stable, and all the tests pass.

I removed all the url-loading tags, since we are now officially living
in the future.
Better Mission/Plot Admin Page

Now you can filter missions by game, define plots inline with missions,
and set a mission's victor or visibility from the mission list.
Migrate from the deprecated localflavor package.
Merge pull request #139 from jthemphill/django_1.5

Upgrade to Django 1.5
Merge pull request #140 from jthemphill/feature/better_missions_admin

Better Mission/Plot Admin Page