SAML

Depends on https://github.com/SURFnet/Stepup-saml-bundle/pull/4
I think @pmeulen can weigh in here, but I always hated how the EngineBlock post screen never really made clear how the minute that the JavaScript is done executing (which is within a ms) the user isn't waiting on us any more, but on the SP (which may actually take quite some time).