Typed class properties (#1426)

lib/SimpleSAML/Auth/AuthenticationFactory.php

lib/SimpleSAML/Auth/ProcessingChain.php

lib/SimpleSAML/Auth/ProcessingFilter.php

lib/SimpleSAML/Auth/Simple.php

lib/SimpleSAML/Auth/Source.php

lib/SimpleSAML/Auth/State.php

lib/SimpleSAML/Command/RouterDebugCommand.php

lib/SimpleSAML/Configuration.php

lib/SimpleSAML/Database.php

lib/SimpleSAML/Error/AuthSource.php

lib/SimpleSAML/Error/BadRequest.php

lib/SimpleSAML/Error/ConfigurationError.php

lib/SimpleSAML/Error/CriticalConfigurationError.php

lib/SimpleSAML/Error/Error.php

lib/SimpleSAML/Error/Exception.php

lib/SimpleSAML/Error/NotFound.php

lib/SimpleSAML/Error/UnserializableException.php

lib/SimpleSAML/HTTP/RunnableResponse.php

lib/SimpleSAML/IdP.php

lib/SimpleSAML/IdP/IFrameLogoutHandler.php