- PEP 3106: dict.iterkeys(), .iteritems(), .itervalues() are now gone;
  and .keys(), .items(), .values() return dict views.

The dict views aren't fully functional yet; in particular, they can't
be compared to sets yet.  but they are useful as "iterator wells".

There are still 27 failing unit tests; I expect that many of these
have fairly trivial fixes, but there are so many, I could use help.
diff --git a/Lib/threading.py b/Lib/threading.py
index e23007e..439a378 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -707,7 +707,7 @@
 
 def enumerate():
     _active_limbo_lock.acquire()
-    active = _active.values() + _limbo.values()
+    active = list(_active.values()) + list(_limbo.values())
     _active_limbo_lock.release()
     return active