Fixed Subscribers' bulk actions when filtering by a segment

- filter by segment is now affected by the selected group (all, trash,...)
- updated relationship methods between subscribers & segments (to account for subsegment status)

lib/Models/Model.php

@@ -110,7 +110,7 @@ class Model extends \Sudzy\ValidModel {
     $total = $orm->count();
 
     if($total > 0) {
-      $models = $orm->select('id')
+      $models = $orm->select(static::$_table.'.id')
         ->offset(null)
         ->limit(null)
         ->findArray();