Add linting to CI (#3)

* Add linting to CI

* Install flake8 and pylint

Author: JeffLIrion

.travis.yml

@@ -18,13 +18,13 @@ cache:
     - $HOME/.cache/pip
 
 install:
-  - pip install tox coveralls
+  - pip install tox coveralls flake8 pylint
 
 env:
   - TOXENV=py36
   - TOXENV=py27
 
-script: tox
+script: flake8 adb/ && pylint adb/ && tox
 
 after_success:
   - coveralls