_init() method doesn't allow plugin to send additional properties with initEnd message

[JamalAkram89]

_init method calls the overridable Init method but then sends the initEnd message to OFS without letting the plugin to make any changes to the initEnd message. The plugin may need to be woken up and complete the initialization in background. The implementing plugin should be allowed to optionally send the following properties in the initEnd message.

   wakeupNeeded: true | false,
   wakeOnEvents: {
      "timer": { 
         wakeupDelay: <Time in Seconds>, 
         sleepTimeout: <Time in Seconds> 
      }
   }