Core and builtins
+- Cycles going through the __class__ link of a new-style instance are
+ now detected by the garbage collector.
+
- Classes using __slots__ are now properly garbage collected.
[SF bug 519621]
Library
+- Some fixes in the copy module: when an object is copied through its
+ __reduce__ method, there was no check for a __setstate__ method on
+ the result [SF patch 565085]; deepcopy should treat instances of
+ custom metaclasses the same way it treats instances of type 'type'
+ [SF patch 560794].
+
- Sockets now support timeout mode. After s.settimeout(T), where T is
a float expressing seconds, subsequent operations raise an exception
if they cannot be completed within T seconds. To disable timeout