refactoring quarantine_list
Adding dbconn and dbclose in postfix_relay.php

closes issue #76
Merge pull request #74 from philrandal/master

Initialize $usertype and $domainname in checklogin.php
Using logical AND where appropriate
Replacing rainingfrog.co.uk with securelist.com, maintained by Kaspersky

fix #37
Added the ability to show/hide the software version page

fix #73