Add Python version trove classifiers

Author: mx-moth

setup.py

@@ -38,6 +38,10 @@ def read(*rnames):
         "License :: OSI Approved :: Apache Software License",
         "Operating System :: OS Independent",
         "Programming Language :: Python",
+        "Programming Language :: Python :: 2",
+        "Programming Language :: Python :: 2.7",
+        "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.5",
         "Topic :: Internet :: WWW/HTTP",
         "Topic :: Internet :: WWW/HTTP :: WSGI",
         "Topic :: Security",