fix classifiers

Author: kmaehashi

setup.py

@@ -23,12 +23,12 @@ def _read(filename):
           'License :: OSI Approved :: MIT License',
           'Programming Language :: Python',
           'Programming Language :: Python :: 2',
-          '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',
       ],
       packages=find_packages(exclude=['atwiki.test']),
       entry_points={