use PHP_VERSION constant

less shellcode, just use PHP_VERSION constant

http://www.php.net//manual/en/reserved.constants.php
Merge pull request #245 from glensc/patch-1

use PHP_VERSION constant
Added PHP 5.6 and HHVM to travis.yml
Merge pull request #255 from Nyholm/patch-1

Added PHP 5.6 and HHVM to travis.yml
Use older PCRE pattern if using a troublesome lib version, fixes #41 and #261
Changelog
Changelog
Merge branch 'master' of https://github.com/PHPMailer/PHPMailer