dictset 0.3.1.2

A specialized Python container datatype for managing collections of sets.

V0.3.1.2 - fixed bug were the intersection with an empty dict returned an empty dict instead of an empty DictSet, also reworked how the this is checked for all the functions in the unit testing.

V0.3.1.1 - refactored .update duck typing

V0.3.1 - added fromkeys classmethod, some cruft removal, PEP8…

V0.3 - defined an __iter__ method to only yield keys to non-empty sets. To iterate over all the sets use .keys()