[Python-3000] Support for PEP 3131

["Martin v. Löwis"]

> I don't think this scenario is all that unlikely. A
> program is initially written by a Russian programmer
> who uses his own version of "a" as a variable name.
> Later an English-speaking programmer makes some
> changes, and uses an ascii "a". Now there are two
> subtly different variables called "a" in different
> parts of the program.

If they work in the same project, they will have a coding
style that says "ASCII-only identifiers".

Also, if the change is in different parts of the program,
there won't be a common variable called "a". When was the
last time you called a variable 'a'? I hope it was a local
variable; if you use 'a' for class or method names, or
global variables, you have bigger problems than
typographical ones.

Regards,
Martin