Update .travis.yml

Author: richmahn

.travis.yml

@@ -4,6 +4,10 @@ python:
 - '3.3'
 - '3.4'
 - '3.5'
+branches:
+  only:
+  - master
+  - develop
 install:
 - pip install -r requirements.txt
 - pip install -r test_requirements.txt