a roundtrip test for boolean values.
unpak true/false values into Data::MessagePack::Boolean objects

utilitiy function load_bool is taken from msgpack-perl:

    https://github.com/msgpack/msgpack-perl/blob/master/xs-src/unpack.c#L55
Merge pull request typester/Data-MessagePack-Stream #5 from gugod/master

roundtrip boolean values

Conflicts:
	src/Data-MessagePack-Stream.xs