Put an updated UserDict class in the collections module and
register it as a compliant Mutable Mapping.

Todo:  Convert the UserDict dependent tests to the new API
       and then remove the old UserDict module.  Move the
       UserDict docs to collections.rst.
diff --git a/Misc/NEWS b/Misc/NEWS
index 921b2a9..5e90be4 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -70,6 +70,13 @@
 Library
 -------
 
+- Weakref dictionaries now inherit from MutableMapping.
+  XXX their API still needs to be modernized (i.e. eliminate the iter methods).
+
+- Created new UserDict class in collections module.  This one inherits from and
+  complies with the MutableMapping ABC.  
+  XXX still need to covert old UserDict based tests and eliminate the old UserDict module.
+
 - Removed UserDict.DictMixin.  Replaced all its uses with collections.MutableMapping.
 
 - Issue #1703: getpass() should flush after writing prompt.