SAML strategy learned `idp_sso_target_url_runtime_params` option.

With this option we can declare params that will be sent to the IdP upon
AuthnRequest if they exist on the original omniauth request phase.
Additionally, these params can be mapped to different keys.
Remove forgotten debug statement.
Use more descriptive names in specs and doc.
Add one more test when idp_sso_target_url_runtime_params are configured but they are absent from the request.
Fallback to omniauth callback url if assertion_consumer_service_url is not set
passing through all options to SAML lib
Merge branch 'rsaml-idp_runtime_params'
Merge branch 'atomicobject-master'
Merge branch 'dei79-respons-options'
no longer set a default `name_identifier_format`.
omniauth-saml 1.1.0