Configuration with defaults

...
      new ConfMailer(
        host            = config.flatOpt("dfe.mailer.host").getOrElse("localhost"),
        port            = config.flatOpt("dfe.mailer.port").getOrElse(25),
        ssl             = config.flatOpt("dfe.mailer.ssl").getOrElse(false),
        tls             = config.flatOpt("dfe.mailer.tls").getOrElse(false),
        user            = config.flatOpt("dfe.mailer.auth.user"),
        password        = config.flatOpt("dfe.mailer.auth.password"),
        mock            = config.flatOpt("dfe.mailer.mock").getOrElse(false),
        from            = config.flatOpt("dfe.mailer.from").getOrElse(""),
        to              = config.flatOpt("dfe.mailer.to").getOrElse("").split(","),
        metricsAnnounce = config.flatOpt("dfe.mailer.metrics-announce").getOrElse("").split(",")m
        tapsAnnounce    = config.flatOpt("dfe.mailer.taps-announce").getOrElse("").split(",")
      ),
...