Version 0.3.2 released

Version 0.3.2 of the python typecheck package is primarily a bug-fix release; over a dozen bugs have been squashed since 0.3.1!

In addition, two new utility classes have been added: Xor() rounds out the collection of boolean utility classes, while YieldSeq() handles generators where the type of the return value differs from yield to yield.

Finally, the Empty() utility class has been extended to work with all iterator types, not just list and dict as before.