message class additions

[morrow95]

    /**
    * The following functions reset the recipient arrays, allowing you to use the same SimpleEmailServiceMessage
    * for multiple API calls without having to reconstruct the entire email each time.
    */
    public function clearTo() {
        $this->to = array();
    }

    public function clearCC() {
        $this->cc = array();
    }

    public function clearBCC() {
        $this->bcc = array();
    }

    public function clearReplyTo() {
        $this->replyto = array();
    }

    public function clearRecipients() {
        $this->clearTo();
        $this->clearCC();
        $this->clearBCC();
        $this->clearReplyTo();
    }
    /**
    * End of added functions
    */