- 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/difflib.py b/Lib/difflib.py
index f2d1343..2dca749 100644
--- a/Lib/difflib.py
+++ b/Lib/difflib.py
@@ -331,7 +331,7 @@
         junkdict = {}
         if isjunk:
             for d in populardict, b2j:
-                for elt in d.keys():
+                for elt in list(d.keys()):
                     if isjunk(elt):
                         junkdict[elt] = 1
                         del d[elt]