setup.py: add Python 3.4 - 3.6 to classifiers

Author: mruffalo

setup.py

@@ -46,6 +46,10 @@
         # that you indicate whether you support Python 2, Python 3 or both.
         'Programming Language :: Python :: 2',
         'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
     ],
 
     # What does your project relate to?