Fix tox environment list

.travis.yml

@@ -1,12 +1,11 @@
 language: python
 python:
-    - "3.5"
+    - "3.6"
 sudo: false
 env:
     - TOXENV=py27
-    - TOXENV=py33
     - TOXENV=py34
-    - TOXENV=py35
+    - TOXENV=py36
 install:
     - pip install -U pip
     - pip install -U Flask tox coverage codecov

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py27, py34, py35, py36
+envlist = py27, py34, py36
 
 [testenv]
 commands =