Try to fix travis

.travis.yml

@@ -1,15 +1,12 @@
 language: python
 python:
-  - 3.3
   - 3.4
+  - 3.5
 
 install:
-- pip install --upgrade setuptools
-- pip install pyflakes
-- pip install pep8
-- pip install coveralls --use-mirrors
-- pip install aiohttp
-- python setup.py develop
+- pip install --upgrade pip
+- pip install -r requirements-dev.txt
+- pip install coveralls
 
 script:
 - pyflakes aiohttp_security tests