[Python-3000] UTF-32 codecs

[Walter Dörwald]

I have a patch against the py3k branch (http://bugs.python.org/1775604)
that adds UTF-32 codecs. On a narrow build it combines surrogate pairs
in the unicode object into one codepoint on encoding and creates
surrogate pairs for codepoints outside the BMP on decoding.

Should I apply this to the py3k branch only, or do we want that for
Python 2.6 too (using str instead of bytes)?

Servus,
   Walter