A little black magic... When the C++ object (for a window or

A little black magic...  When the C++ object (for a window or
whatever) is deleted there is no way to force the Python shadow object
to also be destroyed and clean up all references to it.  This leads to
crashes if the shadow object tries to call a method with the old C++
pointer...  The black magic I've done is to replace the __class__ in the
Python instanc object with a class that raises an exception whenever a
method call is attempted.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15059 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775