Add support for norEduPerson tag in XML CAS response

To allow attributes to be retrieved from <norEduPerson> nested elements when there is no <cas:attributes> available in the XML CAS response file:

<cas:serviceResponse xmlns:cas="http://www.yale.edu/tp/cas">
    <cas:authenticationSuccess>
        <cas:user>UserName</cas:user>
        <norEduPerson>
            <mail>UserEmail</mail>
            <sn>UserLastName</sn>
            <gn>UserFirstName</gn>
        </norEduPerson>
    </cas:authenticationSuccess>
</cas:serviceResponse>