[Python-3000] IDLE encoding setup

["Martin v. Löwis"]

> The changes you checked in to _tkinter.c fixed WidgetRedirector, and
> those and the other changes you made in idlelib have IDLE working
> without the subprocess.
> 
> Thanks very much for working on this!

I doubt that all is working yet, though. So some thorough testing would
probably be necessary - plus getting the subprocess case to work, of
course.

Regards,
Martin