[gcs-jards-#70] Improve documentation for listener

lib/EventListener.php

@@ -12,7 +12,7 @@ interface EventListener{
 	 * This is called for every new received event.
 	 * The event is provided in two formats: simple JSON decoded object and Swagger deserialized model.
 	 * 
-	 * @param object $event encoded object from JSON
+	 * @param object $event encoded object from JSON, you could call json_encode($event) to get it as a string
 	 * @param \jards\eventsapiclient\Swagger\Client\Model\Event $event deserialized event ino Swagger model
 	 */
 	public function handleEvent($jsonevent, $apievent);

lib/MailOnEventListener.php

@@ -58,7 +58,7 @@ class MailOnEventListener implements EventListener{
 	 */
 	public function handleEvent($jsonevent, $apievent){
 		$config = parse_ini_file(__DIR__.'/../configs/mail.cnf');
-		$this->sendmail($config['TARGET'], 'New event received', json_encode($jsonevent));
+		$this->sendmail($config['TARGET'], 'New event received over '.gethostname(), json_encode($jsonevent));
 	}
 }