errors in core spec examples

Attached zip file has corrected XML for examples in core spec.  Main
corrections are:

 * set namespace to
"urn:oasis:names:tc:xacml:3.0:core:schema:wd-12" (was
"urn:oasis:names:tc:xacml:3.0:schema:wd-12"

 * Put IncludeInResult attribute on Attribute element instead of
Attributes element.

Regards,
--Paul