Made some improvements to ACL system including: warning on setting Deny for Everyone on the entire site, added ACL_ALWAYS_ALLOW_ADMIN_EDIT_ACL, and changed behavior as noted in the docs so that Deny for Everyone is no longer able to be overridden

<?php
class Text_Wiki_Render_Plain_Include extends Text_Wiki_Render {    
    function token()
    {
        return '';
    }
}
?>