[Python-3000] Support for PEP 3131

["Martin v. Löwis"]

>> People should not have to read long system configuration pages
>> just to run the program that they intuitively wrote correctly
>> right from the start.
> 
> It is not intuitive.  One thing I learned from the discussion here
> about Unicode identifiers in other languages is that, though this
> support exists in several other languages, it is *different* in each
> of them.  And PEP 3131 is different still.  They allow different
> sets of characters, and even worse, use different normalization rules.

This is a theoretical problem only. People intuitively know what a
"word" is in their language, and now we tell them they can use
words as identifiers, as long as there are no spaces in them.

That different (programming) languages encode that intuition
in slightly different rules makes no practical difference:
the actual differences are only in boundary cases that are
unlikely to occur in real life (unless somebody deliberately
tries to come up with border cases).

Regards,
Martin