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/Misc/NEWS b/Misc/NEWS
index 41b8ab1..c79b531 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -31,6 +31,9 @@
 - io.open() and _fileio.FileIO have grown a new argument closefd. A false
   value disables the closing of the file descriptor.
 
+- Added a new option -b to issues warnings (-bb for errors) about certain
+  operations between bytes/buffer and str like str(b'') and comparsion.
+
 Extension Modules
 -----------------