Step 3 sender and reply to per newsletter

- added sender_address/sender_name/reply_to_address/reply_to_name
- added validation on all form fields (except checkbox and radio)

lib/Config/Menu.php

@@ -320,8 +320,6 @@ class Menu {
   }
 
   function newsletters() {
-    add_filter('heartbeat_received', array($this, 'getQueueStatus'), 10, 3);
-
     global $wp_roles;
 
     $data = array();
@@ -332,15 +330,6 @@ class Menu {
     echo $this->renderer->render('newsletters.html', $data);
   }
 
-  function getQueueStatus($response, $data, $screen_id) {
-    if(isset($data['mailpoet'])) {
-        $response['mailpoet'] = array(
-            'hello' => 'world'
-        );
-    }
-    return $response;
-  }
-
   function newletterEditor() {
     $data = array();
     wp_enqueue_media();