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_unicodedata.py b/Lib/test/test_unicodedata.py
index ff2dcf5..ba97e5d 100644
--- a/Lib/test/test_unicodedata.py
+++ b/Lib/test/test_unicodedata.py
@@ -176,7 +176,8 @@
 
     def test_east_asian_width(self):
         eaw = self.db.east_asian_width
-        self.assertRaises(TypeError, eaw, str8(b'a'))
+        self.assertRaises(TypeError, eaw, b'a')
+        self.assertRaises(TypeError, eaw, buffer())
         self.assertRaises(TypeError, eaw, '')
         self.assertRaises(TypeError, eaw, 'ra')
         self.assertEqual(eaw('\x1e'), 'N')