Drop support for EOL Python 3.3

Author: hugovk

.travis.yml

@@ -2,7 +2,6 @@ language: python
 python:
   - 2.6
   - 2.7
-  - 3.3
   - 3.4
   - 3.5
   - 3.6

setup.py

@@ -161,7 +161,7 @@
             ],
     },
     install_requires=['PyOpenSSL', 'pyasn1>=0.1.1'],
-    python_requires='>=2.6, !=3.0.*, !=3.1.*, !=3.2.*',
+    python_requires='>=2.6, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*',
     classifiers=[
         'Development Status :: 5 - Production/Stable',
         'Environment :: Console',
@@ -179,7 +179,6 @@
         'Programming Language :: Python :: 2.6',
         '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',