update Python version classifiers:

- drop specific 3.x
- drop 2.6

IPython/core/release.py

@@ -141,11 +141,8 b' classifiers = ['
     'License :: OSI Approved :: BSD 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 :: 3.2',
-    'Programming Language :: Python :: 3.3',
     'Topic :: System :: Distributed Computing',
     'Topic :: System :: Shells'
     ]