Added generic Python 2 and Python 3 classifiers

Author: MarkusH

setup.py

@@ -40,7 +40,9 @@
         "License :: OSI Approved :: MIT License",
         "Operating System :: OS Independent",
         "Programming Language :: Python",
+        "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 2.7",
+        "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3.3",
         "Programming Language :: Python :: 3.4",
         "Programming Language :: Python :: 3.5",