- Refactors Mailer class

- Refactors SendingQueue worker class
- Adds Maier router with a send() method + ability to specify sending method
- Updates tests
- Introduces 'stopping' and 'starting' cron states
- Improves cron control mechanism
Closes #276

lib/Router/SendingQueue.php

@@ -19,7 +19,6 @@ class SendingQueue {
           'errors' => array($e->getMessage())
         )
       );
-      exit;
     }
 
     $queue = \MailPoet\Models\SendingQueue::where('newsletter_id', $data['newsletter_id'])