Add entry point for ipythonx to setup.py, when used with setuptools.

setup.py

@@ -132,7 +132,8 b" if 'setuptools' in sys.modules:"
             'pycolor = IPython.PyColorize:main',
             'ipcontroller = IPython.kernel.scripts.ipcontroller:main',
             'ipengine = IPython.kernel.scripts.ipengine:main',
-            'ipcluster = IPython.kernel.scripts.ipcluster:main'
+            'ipcluster = IPython.kernel.scripts.ipcluster:main',
+            'ipythonx = IPython.frontend.wx.ipythonx:main'
         ]
     }
     setup_args["extras_require"] = dict(