[Python-3000] C API cleanup str

[Guido van Rossum]

Do you guys need more guidance on this? It seems Martin's checkin
didn't make things worse in the tests deparment -- I find (on Ubuntu)
that test_ctypes is now failing, but test_threaded_import started
passing.

One issue with just putting this in the C API docs is that I believe
(tell me if I'm wrong) that these haven't been kept up to date in the
struni branch so we'll need to make a lot more changes than just this
one...

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)