Undo previous travis change. Set python to 3.5 globally.

.travis.yml

@@ -1,22 +1,19 @@
 language: python
-python: 2.7
+python: 3.5
 os:
   - linux
 #  - osx
 env:
   - TOX_ENV=py27
+  - TOX_ENV=py35
   - TOX_ENV=pypy
 matrix:
   fast_finish: true
-  include:
-    - python: 3.5
-      env:
-      - TOXENV=py35
   allow_failures:
     - os: osx
 install:
   - pip install tox
   - pip install coveralls
 script:
-  - tox
+  - tox -e $TOX_ENV
 after_success: coveralls