SF patch# 1770008 by Christian Heimes (plus some extras).

Completely get rid of StringIO.py and cStringIO.c.

I had to fix a few tests and modules beyond what Christian did, and
invent a few conventions.  E.g. in elementtree, I chose to
write/return Unicode strings whe no encoding is given, but bytes when
an explicit encoding is given.  Also mimetools was made to always
assume binary files.

Lib/logging/__init__.py

@@ -26,7 +26,7 @@ Copyright (C) 2001-2007 Vinay Sajip. All Rights Reserved.
 To use, simply 'import logging' and log away!
 """
 
-import sys, os, time, cStringIO, traceback
+import sys, os, time, io, traceback
 
 try:
     import codecs
@@ -396,7 +396,7 @@ class Formatter:
         This default implementation just uses
         traceback.print_exception()
         """
-        sio = cStringIO.StringIO()
+        sio = io.StringIO()
         traceback.print_exception(ei[0], ei[1], ei[2], None, sio)
         s = sio.getvalue()
         sio.close()