unfriendly error handling with pythonw and ipython-qtconsole

[mwiebe]

See issue #1436. The following is copy/pasted from a comment there:

Behavior of ipython-qtconsole.exe and "pythonw ipython-qtconsole-script.pyw" is very unhelpful when it errors. It assumes users will see the message printed to the console. They will not, and just assume ipython has poor quality standards. ;) If IPython detected it was run with pythonw, it could pop up a message box instead of just printing to the nonexistent console and exiting. This is also important for the case where dependencies like pyside/pyqt are not installed.

C:\>python "C:\Python27\Scripts\ipython-qtconsole-script.pyw" --gui qt
IPython: an enhanced interactive Python shell.

Options
-------
<SNIP>
To see all available configurables, use `--help-all`

[IPKernelApp] Bad config encountered during initialization:
[IPKernelApp] Unrecognized flag: '--gui'
<HANG>

[takluyver]

If we don't have PySide/PyQt, do we have any reliably available means to pop up an error?

[mwiebe]

Yes, we can use ctypes to call the MessageBox function.

http://msdn.microsoft.com/en-us/library/windows/desktop/ms645505(v=vs.85).aspx