Initial attempt at travis integration
Add mongodb service requirement
Remove Python 3.2

3.2 build failed, 2.6 and 2.7 builds passed. Don't need 3.2 support
yet, so removing for now.

See https://travis-ci.org/alphagov/backdrop/builds/6513232
Merge pull request #62 from alphagov/travis-ci

Travis CI
Merge branch 'master' into cache-control