Finish SF patch 477059:  __del__ on new classes vs. GC.
Just doc and NEWS here, about the change in gc.garbage meaning.
diff --git a/Misc/NEWS b/Misc/NEWS
index 02c4928..c0f09ae 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -32,6 +32,11 @@
 
 Extension modules
 
+- By default, the gc.garbage list now contains only those instances in
+  unreachable cycles that have __del__ methods; in 2.1 it contained all
+  instances in unreachable cycles.  "Instances" here has been generalized
+  to include instances of both new-style and old-style classes.
+
 - The socket module defines a new method for socket objects,
   sendall().  This is like send() but may make multiple calls to
   send() until all data has been sent.  Also, the socket function has