Update invoke version; run lint command for app's travis builds

.travis.yml

@@ -8,6 +8,6 @@ python:
   - 3.5
 install:
   - pip install cookiecutter
-  - pip install invoke==0.9.0
+  - pip install invoke==0.12.2
 script:
   - invoke test

{{cookiecutter.app_name}}/.travis.yml

@@ -5,5 +5,7 @@ python:
   - 2.7
   - 3.3
   - 3.4
+  - 3.5
 install: pip install -r requirements/dev.txt
-script: py.test tests
+before_script: python manage.py lint
+script: python manage.py test