Test upgrade

- use tox for reproductible test suite
- separate qa check in another job
- use django-dbdiff to remove technical debt
- upgrade django-responsediff, indent fixture json

.travis.yml

@@ -1,7 +1,9 @@
 sudo: false
 language: python
 env:
-- DJANGO="django>1.8,<1.9" DJANGO_SETTINGS_MODULE=representatives.tests.settings
+  matrix:
+  - TOXENV=py27-dj18
+  - TOXENV=qa
 python:
 - "2.7"
 before_install:
@@ -10,11 +12,6 @@ install:
 - pip install $DJANGO pep8 flake8 pytest-django pytest-cov codecov django-responsediff
 - pip install -e .[api]
 script:
-- pep8 representatives/ --exclude migrations --ignore E128
-- flake8 representatives/ --exclude migrations --ignore E128
-- django-admin migrate
-- cat representatives/contrib/francedata/tests/representatives_input.json | francedata_import_representatives
-- cat representatives/contrib/parltrack/tests/representatives_fixture.json | parltrack_import_representatives
-- py.test
+- tox
 after_success:
 - codecov