Udating PHPMailer to version 5.2.3.

There was a bug in 5.2.2 occuring on some systems (including mine)

see Issue 134: https://code.google.com/a/apache-extras.org/p/phpmailer/issues/detail?id=140&can=1&start=100

Note: This version is faulty marked as 5.2.2 (see https://code.google.com/a/apache-extras.org/p/phpmailer/source/browse/tags/5.2.3/class.phpmailer.php)
Merge pull request #1830 from piotr-cz/patch_PHPMailer_5.2.3

Udating PHPMailer to version 5.2.3.