[Python-3000] UTF-32 codecs

["Martin v. Löwis"]

> OK, then I'll check it into the py3k branch, and backport it to the trunk.

This raises another procedural question: are we still merging from the
trunk to the 3k branch, or are they now officially split?

If we still merge, and assuming that the implementations are
sufficiently similar and live in the same files, it would be better
to commit into the trunk, then merge (or wait for somebody else to
merge), then apply any modifications that the 3k branch needs.

Regards,
Martin