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/Lib/test/test_pickle.py b/Lib/test/test_pickle.py
index 11254f4..f54381f 100644
--- a/Lib/test/test_pickle.py
+++ b/Lib/test/test_pickle.py
@@ -10,6 +10,9 @@
 
 class PickleTests(AbstractPickleTests, AbstractPickleModuleTests):
 
+    module = pickle
+    error = KeyError
+
     def dumps(self, arg, proto=0, fast=0):
         # Ignore fast
         return pickle.dumps(arg, proto)
@@ -18,9 +21,6 @@
         # Ignore fast
         return pickle.loads(buf)
 
-    module = pickle
-    error = KeyError
-
 class PicklerTests(AbstractPickleTests):
 
     error = KeyError