- 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/_strptime.py b/Lib/_strptime.py
index e389ce7..10b0083 100644
--- a/Lib/_strptime.py
+++ b/Lib/_strptime.py
@@ -338,7 +338,7 @@
     # values
     weekday = julian = -1
     found_dict = found.groupdict()
-    for group_key in found_dict.iterkeys():
+    for group_key in found_dict.keys():
         # Directives not explicitly handled below:
         #   c, x, X
         #      handled by making out of other directives