Added PHP 7 check in installer and updater.

Till Brehm

2016-04-22 ebd0e986ed11f2a34fb58cdd33efbfab192083ad

 interface/lib/classes/tform.inc.php

@@ -691,10 +691,6 @@
            unset($_POST);
            unset($record);
         }
         $_SESSION['_csrf'][$_csrf_id] = null;
         $_SESSION['_csrf_timeout'][$_csrf_id] = null;
         unset($_SESSION['_csrf'][$_csrf_id]);
         unset($_SESSION['_csrf_timeout'][$_csrf_id]);
         
         if(isset($_SESSION['_csrf_timeout']) && is_array($_SESSION['_csrf_timeout'])) {
            $to_unset = array();