ipython_shell.py issues

This problem seems to have been mentioned many years ago in issue #1 (number 1!).
But when running this example on wx I still see:

```
(wx-env-pyface)~/Desktop/pyface/examples aayres (master) $ python ipython_shell.py
01:47:39 PM: Debug: Adding duplicate image handler for 'Windows bitmap file'
01:47:39 PM: Debug: Adding duplicate image handler for 'Windows bitmap file'
01:47:39 PM: Debug: Adding duplicate image handler for 'Windows bitmap file'
/Users/aayres/.edm/envs/wx-env-pyface/lib/python3.6/site-packages/IPython/frontend.py:21: ShimWarning: The top-level `frontend` package has been deprecated since IPython 1.0. All its subpackages have been moved to the top `IPython` level.
"All its subpackages have been moved to the top `IPython` level.", ShimWarning)
Traceback (most recent call last):
File "ipython_shell.py", line 15, in
from pyface.ipython_widget import IPythonWidget
File "/Users/aayres/Desktop/pyface/pyface/ipython_widget.py", line 28, in
IPythonWidget = toolkit_object("ipython_widget:IPythonWidget")
File "/Users/aayres/Desktop/pyface/pyface/base_toolkit.py", line 146, in __call__
module = import_module(mname, package)
File "/Users/aayres/.edm/envs/wx-env-pyface/lib/python3.6/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "/Users/aayres/Desktop/pyface/pyface/ui/wx/ipython_widget.py", line 23, in
from IPython.frontend.wx.wx_frontend import WxController
ModuleNotFoundError: No module named 'IPython.frontend.wx'
```

and on qt:

```
(qt-env-pyface)~/Desktop/pyface/examples aayres (master) $ python ipython_shell.py
/Users/aayres/.edm/envs/qt-env-pyface/lib/python3.6/site-packages/IPython/frontend.py:21: ShimWarning: The top-level `frontend` package has been deprecated since IPython 1.0. All its subpackages have been moved to the top `IPython` level.
"All its subpackages have been moved to the top `IPython` level.", ShimWarning)
Traceback (most recent call last):
File "ipython_shell.py", line 48, in
window.open()
File "/Users/aayres/.edm/envs/qt-env-pyface/lib/python3.6/site-packages/pyface/i_window.py", line 203, in open
self._create()
File "/Users/aayres/.edm/envs/qt-env-pyface/lib/python3.6/site-packages/pyface/ui/qt4/application_window.py", line 134, in _create
contents = self._create_contents(self.control)
File "ipython_shell.py", line 36, in _create_contents
self._shell = IPythonWidget(parent)
File "/Users/aayres/.edm/envs/qt-env-pyface/lib/python3.6/site-packages/pyface/base_toolkit.py", line 184, in __init__
raise NotImplementedError(msg % (toolkit, package, name))
NotImplementedError: the qt4 pyface.ui.qt4 backend doesn't implement ipython_widget:IPythonWidget
```