Added support for Libraries API.
Changes since BETA 1
#642138 by Zoltok, sun, smk-ka: Fixed wrong path to class.smtp.php.
#686994 by sun, smk-ka: Restored compatibility with PHPMailer 2.x library.
#675388 by smk-ka: Fixed unrecognized character in regular expression for PHP versions < 5.2.2.
#607204 by dagmar, smk-ka: Fixed unable to reply to e-mails sent via Google Mail. Added an option to always set a "Reply-To" address.