update travis.yml

Author: be-hase

.travis.yml

@@ -1,25 +1,11 @@
 language: python
 
-env:
-  matrix:
-    - python: 2.7
-      env: TOXENV=py27
-    - python: 3.3
-      env: TOXENV=py33
-    - python: 3.4
-      env: TOXENV=py34
-    - python: 3.5
-      env: TOXENV=py35
-    - python: 3.5
-      env: TOXENV=py35-flake8-src
-    - python: 3.5
-      env: TOXENV=py35-flake8-tests
-  fast_finish: true
-  allow_failures:
-    - env: TOXENV=py35-flake8-src
-    - env: TOXENV=py35-flake8-tests
+python:
+  - "2.7"
+  - "3.3"
+  - "3.4"
+  - "3.5"
 
-install:
-  - pip install tox
+install: pip install tox-travis
 
 script: tox