Consolidate CI tools into setup.cfg and drop tox

.travis.yml

@@ -9,16 +9,14 @@ sudo: false
 matrix:
     include:
         - python: 3.4
-          env: TOXENV=py34
         - python: 3.5
-          env: TOXENV=py35
         - python: 3.6
-          env: TOXENV=py36
         - python: 3.6
-          env: TOXENV=pycodestyle
 
 install:
     - pip install --requirement requirements.txt
-    - pip install tox
 
-script: tox -c src/tox.ini
+script:
+    - pytest src/
+    - pycodestyle src/
+    - coveralls