Allow configuration of multiple SAML providers
https://www.pivotaltracker.com/story/show/76918956

cf-properties.yml:
  Allow any configuration under login.saml to be merged in, even child objects
spec:
  Document spec file and deprecate not used properties
  Add in socket options for SAML HTTP metadata requests
login.yml.erb:
  Support new configuration options
  Represent long strings in a cleaner format,
  without the need for duplicate line feeds