Add support for PyPy

issue4408

setup.py

@@ -93,6 +93,8 @@ setup(name=name,
         'Natural Language :: Spanish',
         'Operating System :: OS Independent',
         'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: Implementation :: CPython',
+        'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Office/Business',
         'Topic :: Office/Business :: Financial :: Accounting',
         ],