Use tox-travis when running tests on travis

This means we can now run tests against Python 3.5 and 3.6, where
previously we could not.

.travis.yml

@@ -1,7 +1,10 @@
 language: python
 sudo: false
 python:
+  - 2.7
+  - 3.4
   - 3.5
+  - 3.6
 cache:
   directories:
     - $HOME/.cache/pip
@@ -9,7 +12,7 @@ services:
   - postgresql
   - mysql
 install:
-  - pip install tox
+  - pip install tox-travis
 before_script:
   - mysql -e 'create database test_project';
   - psql -c 'create database test_project;' -U postgres;

tox.ini

@@ -2,6 +2,7 @@
 envlist =
     coverage-erase
     {py27,py34,py35}-django{18,19,110,111}-{sqlite,postgres,mysql}
+    py36-django111-{sqlite,postgres,mysql}
     coverage-report
     flake8
 
@@ -22,6 +23,13 @@ commands =
     mysql: coverage run -a tests/runtests.py -d mysql
     coverage-report: coverage report
 
+[travis]
+python =
+    2.7: py27
+    3.4: py34
+    3.5: py35, flake8
+    3.6: py36
+
 [flake8]
 max-line-length=120
 exclude=build,venv,migrations,south_migrations,.tox