Updates to the with-statement:

- New semantics for __exit__() -- it must re-raise the exception
  if type is not None; the with-statement itself doesn't do this.
  (See the updated PEP for motivation.)

- Added context managers to:
  - file
  - thread.LockType
  - threading.{Lock,RLock,Condition,Semaphore,BoundedSemaphore}
  - decimal.Context

- Added contextlib.py, which defines @contextmanager, nested(), closing().

- Unit tests all around; bot no docs yet.
diff --git a/Misc/NEWS b/Misc/NEWS
index 5599ba5..51e0aef 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -36,6 +36,12 @@
   with_statement``. Use of 'with' as a variable will generate a warning.
   Use of 'as' as a variable will also generate a warning (unless it's
   part of an import statement).
+  The following objects have __context__ methods:
+  - The built-in file type.
+  - The thread.LockType type.
+  - The following types defined by the threading module:
+    Lock, RLock, Condition, Semaphore, BoundedSemaphore.
+  - The decimal.Context class.
 
 - Fix the encodings package codec search function to only search
   inside its own package. Fixes problem reported in patch #1433198.
@@ -411,6 +417,9 @@
 Library
 -------
 
+- PEP 343: new module contextlib.py defines decorator @contextmanager
+  and helpful context managers nested() and closing().
+
 - The compiler package now supports future imports after the module docstring.
 
 - Bug #1413790: zipfile now sanitizes absolute archive names that are