Create os.fsdecode(): decode from the filesystem encoding with surrogateescape
error handler, or strict error handler on Windows.

 * Rewrite os.fsencode() documentation
 * Improve os.fsencode and os.fsdecode() tests using the new PYTHONFSENCODING
   environment variable
diff --git a/Doc/whatsnew/3.2.rst b/Doc/whatsnew/3.2.rst
index 3927f4b..2ec93d2 100644
--- a/Doc/whatsnew/3.2.rst
+++ b/Doc/whatsnew/3.2.rst
@@ -237,13 +237,16 @@
 * Stub
 
 
-Unicode
-=======
+Filenames and unicode
+=====================
 
 The filesystem encoding can be specified by setting the
 :envvar:`PYTHONFSENCODING` environment variable before running the interpreter.
 The value should be a string in the form ``<encoding>``, e.g. ``utf-8``.
 
+The :mod:`os` module has two new functions: :func:`os.fsencode` and
+:func:`os.fsdecode`.
+
 
 IDLE
 ====