Put a space before the exclamation mark in the Twitter message

Some clients apparently were unable to separate the url from the
exclamation mark, leading to a few easily avoidable 404s.
Time stamp quizzes, and make them searchable in admin

All quizzes are now timestamped with their creation time. This makes it
easier to debug error messages, since I can see if the quiz was created
before or after a particular fix.

Quizzes are now displayed in the admin interface, searchable by key.
This also makes it easier to investigate errors.
Merge branch 'master' of github.com:knatten/cppquiz
Fabric now always runs all tests before deploying
Fix broken test