Updating the SAML 2.0 authnresponse generation to use the new API in...

Updating the SAML 2.0 authnresponse generation to use the new API in xmlseclibs for adding reference ID attribute... Basicly an updated needed to make the saml 2 part work with the new xmlseclib version

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@176 44740490-163a-0410-bde0-09ae8108e29a