More C++-compliance. Note especially listobject.c - to get C++ to accept the

More C++-compliance. Note especially listobject.c - to get C++ to accept the
PyTypeObject structures, I had to make prototypes for the functions, and
move the structure definition ahead of the functions. I'd dearly like a better
way to do this - to change this would make for a massive set of changes to
the codebase.

There's still some warnings - this is purely to get rid of errors first.