#114 fix if empty

cartable/cartable.php

@@ -897,6 +897,9 @@ function cartable_civicrm_alterCustomFieldDisplayValue(&$displayValue, $value, $
                 </thead>
                 <tbody>';
             foreach($rows as $row){
+                if(empty($row)) {
+                    continue;
+                }
                 $cols = explode('|', $row);
                 $html.='
                     <tr><td>'.trim($cols[0]).'</td><td>'.trim($cols[1]).'€</td></tr>';