Make TypedDict.__setitem__ tolerant to missing allowed_values
Make TypedDict.__setitem__ tolerant to missing allowed_values

Before this changeset, TypedDict could not be unpickled because it
defines a __setitem__() method that is called instead of
dict.__setitem__() during unpickling while populating the __dict__ of
the new object. Since allowed_values was required to exist before
calling __setitem__(), an exception would be raised.

tulip-control/tulip-control,necozay/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control