Make Travis-CI use Tox for test matrix execution
Make Travis-CI use Tox for test matrix execution

see http://jsatt.com/blog/using-tox-with-travis-ci-to-test-django-apps/

ericdwang/django-analytical,machtfit/django-analytical,ChristosChristofidis/django-analytical,bittner/django-analytical,apocquet/django-analytical,pjdelport/django-analytical,jcassee/django-analytical