Fix error on listEvaluation

- force default calcDate
- Export / UserHelper: handle case when a single user is given, when we expect more than one user

src/Bundle/ChillMainBundle/Export/Helper/UserHelper.php

@@ -92,6 +92,11 @@ class UserHelper
             }
             $asStrings = [];
 
+            if (array_key_exists('uid', $decoded) || is_numeric($decoded)) {
+                // this is a single value. We have to wrap it into an array
+                $decoded = [$decoded];
+            }
+
             foreach ($decoded as $userId) {
                 if (is_array($userId)) {
                     $uid = $userId['uid'];