More or less implemeted the last part of the SAML 2.0 Metadata XML task item....

More or less implemeted the last part of the SAML 2.0 Metadata XML task item. Done a bit testing, but still at an early stage...

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@154 44740490-163a-0410-bde0-09ae8108e29a