Drop support for EOL Python 3.3

Author: hugovk

setup.py

@@ -36,7 +36,6 @@
           "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",