Update trove classifiers to include pypy and cpython 3.4.

setup.py

@@ -97,6 +97,9 @@ setup(name='dulwich',
           'License :: OSI Approved :: GNU General Public License v2 or later (GPLv2+)',
           'Programming Language :: Python :: 2.6',
           'Programming Language :: Python :: 2.7',
+          'Programming Language :: Python :: 3.4',
+          'Programming Language :: Python :: Implementation :: CPython',
+          'Programming Language :: Python :: Implementation :: PyPy',
           'Operating System :: POSIX',
           'Topic :: Software Development :: Version Control',
       ],