Drop Python 3.3 support

Python 3.3 has reached its end-of-life on Sep 29, 2017. A lot of tools
dropped to support it including pytest which we use for tests. So let's
get rid of this as no one use it anyway. :)

.travis.yml

@@ -5,8 +5,6 @@ matrix:
   include:
     - python: 2.7
       env: TOXENV=py27
-    - python: 3.3
-      env: TOXENV=py33
     - python: 3.4
       env: TOXENV=py34
     - python: 3.5

CHANGES

@@ -5,6 +5,11 @@
 Here you can see the list of changes between each 'sphinxcontrib-openapi'
 release.
 
+0.3.3 (unreleased)
+==================
+
+- Drop Python 3.3 support because it reached its end-of-life.
+
 0.3.2 (2017-10-05)
 ==================
 

setup.py

@@ -44,9 +44,9 @@
         'Programming Language :: Python :: 2',
         'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.3',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
     ],
     namespace_packages=['sphinxcontrib'],
 )

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py27, py33, py34, py35, py36, docs
+envlist = py27, py34, py35, py36, docs
 
 [testenv]
 deps =