[Python-3000] Support for PEP 3131

["Martin v. Löwis"]

> One reason this matters -- even when the original author had good
> intentions -- is that I edit my code as text, rather than graphics.  I
> will often retype rather than cutting and pasting.  Since тор and нтер
> are not the same as the visually similar Top and HTep, that will
> eventually cause problems.

It's actually unlikely that you encounter "тор" or "нтер" - they
don't mean anything in Russian (FWIW, интерпретатор means interpreter;
so "тор" is akin "ter" and "нтер" akin "nter").

I cannot believe that you would actually consider retyping code
that contains Cyrillic characters (you won't understand what it does,
would you?), and even if you did - how would an ASCII-only flag
on the interpreter help? If you type Top and HTep (again, please
look in my eyes and tell me that you would *actually* type in
these identifiers), the error in the interpreter won't trigger.

Regards,
Martin