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/test/test_robotparser.py

@@ -1,4 +1,5 @@
-import unittest, StringIO, robotparser
+import unittest, robotparser
+import io
 from test import test_support
 
 class RobotTestCase(unittest.TestCase):
@@ -32,7 +33,7 @@ tests = unittest.TestSuite()
 def RobotTest(index, robots_txt, good_urls, bad_urls,
               agent="test_robotparser"):
 
-    lines = StringIO.StringIO(robots_txt).readlines()
+    lines = io.StringIO(robots_txt).readlines()
     parser = robotparser.RobotFileParser()
     parser.parse(lines)
     for url in good_urls: