Add dependency on entrypoints

Author: takluyver

setup.py

@@ -82,6 +82,7 @@ def run(self):
         'jupyter_core',
         'pyzmq>=13',
         'python-dateutil>=2.1',
+        'entrypoints',
     ],
     extras_require   = {
         'test': ['ipykernel', 'ipython', 'mock', 'pytest'],