Add license trove classifier

Author: johnthagen

setup.py

@@ -10,7 +10,8 @@
       platforms='Cross platform (Linux, Mac OSX, Windows)',
       license="BSD",
       python_requires='>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*',
-      classifiers=['Development Status :: 4 - Beta',
+      classifiers=['License :: OSI Approved :: BSD License',
+                   'Development Status :: 4 - Beta',
                    'Programming Language :: Python :: 2',
                    'Programming Language :: Python :: 2.7',
                    'Programming Language :: Python :: 3',