Adds a simple referral feature
Author: Derek Barnstorm - updated for 2.6 by Dandello

Installation
------------
1) Modify YaBB files using BoardMod or manually.
2) Upload modified files to your server in ASCII mode.

Files to edit
-------------
Admin/ModList.pm
Languages/English/Email.lng
Languages/English/Profile.lng
Languages/English/Register.lng
Sources/Profile.pm
Sources/Register.pm
Sources/System.pm
Templates/default/Register.template