Added PHPMailer support.

I added in support for PHPMailer 5.2.9. Now users can configure mail delivery via a remote SMTP server without advanced php.ini configuration. Simply editing their settings.php will be sufficient. 

As this is my first PR for nZEDb I'm sure i'll need to fix some things. Please let me know and I'll get right on it. 

I wasn't sure If I should be the one to update the changelog or not as well as how do we handle people upgrading. How do we get the new settings into their settings.php? I set it up so if they don't add the new settings, it will fallback to using the old php mail() method silently.