Merging the py3k-pep3137 branch back into the py3k branch.
No detailed change log; just check out the change log for the py3k-pep3137
branch.  The most obvious changes:

  - str8 renamed to bytes (PyString at the C level);
  - bytes renamed to buffer (PyBytes at the C level);
  - PyString and PyUnicode are no longer compatible.

I.e. we now have an immutable bytes type and a mutable bytes type.

The behavior of PyString was modified quite a bit, to make it more
bytes-like.  Some changes are still on the to-do list.
diff --git a/Objects/fileobject.c b/Objects/fileobject.c
index 97c2756..c6c7d8e 100644
--- a/Objects/fileobject.c
+++ b/Objects/fileobject.c
@@ -146,7 +146,7 @@
 	if (writer == NULL)
 		return -1;
 	if (flags & Py_PRINT_RAW) {
-		value = _PyObject_Str(v);
+		value = PyObject_Str(v);
 	}
 	else
 		value = PyObject_Repr(v);