Sorting for all listings & bugfixes for all listings except Newsletters

- newsletters listing now uses hash history
- newsletters are sorted by Subject (a->z)
- segments are sorted by Name (a->z)
- re-added WordPress Users list as a segment you can send a newsletter to
- added explicit error messages when an auto newsletter isn't fully configured
- added missing strings for "selectAll" in Segments listing
- fixed filters() in Subscribers listing (wrong count as it was not taking groups/filters/search into account)

lib/Models/Segment.php

@@ -132,10 +132,11 @@ class Segment extends Model {
 
   static function groupBy($orm, $group = null) {
     if($group === 'trash') {
-      return $orm->whereNotNull('deleted_at');
+      $orm->whereNotNull('deleted_at');
     } else {
-      $orm = $orm->whereNull('deleted_at');
+      $orm->whereNull('deleted_at');
     }
+    return $orm;
   }
 
   static function getSegmentsWithSubscriberCount() {