Add some trove classifiers, especially the Python :: 2.x ones.

Apparently we still care about 2.4 in this package.  Thanks, buildbots, for
letting me know!  ;)

setup.py

@@ -38,6 +38,22 @@
           open('README.txt').read(),
           open('CHANGES.txt').read(),
           ]),
+      classifiers=[
+          'Development Status :: 5 - Production/Stable',
+          'Environment :: Web Environment',
+          'Intended Audience :: Developers',
+          'License :: OSI Approved :: Zope Public Licence',
+          'Programming Language :: Python',
+          'Programming Language :: Python :: 2',
+          'Programming Language :: Python :: 2.4',
+          'Programming Language :: Python :: 2.5',
+          'Programming Language :: Python :: 2.6',
+          'Programming Language :: Python :: 2.7',
+          'Operating System :: OS Independent',
+          'Topic :: Internet :: WWW/HTTP',
+          'Topic :: Communications :: Email',
+          'Framework :: Zope3',
+      ],
       packages=find_packages('src'),
       package_dir={'': 'src'},
       namespace_packages=['zope',],