Updated UdtWrapper for YAXNamespaceAttribute
Updated UdtWrapper for YAXNamespaceAttribute

Should make it possible for the UdtWrapper to determine whether or not
the YAXNamespaceAttribute is present, and if it is, expose the values
presented by it to the rest of YAXLib's serialization code.

gingsjo/YAXLib,sinairv/YAXLib,gingsjo/YAXLib