Added a new method to check if an event has any listeners registered.

src/Composer/EventDispatcher/EventDispatcher.php

@@ -220,6 +220,19 @@ class EventDispatcher
         return call_user_func_array('array_merge', $listeners[$event->getName()]);
     }
 
+    /**
+     * Checks if an event has listeners registered
+     *
+     * @param Event $event
+     * @return boolean
+     */
+    public function hasEventListeners(Event $event)
+    {
+        $listeners = $this->getListeners($event);
+
+        return (sizeof($listeners) > 0);
+    }
+
     /**
      * Finds all listeners defined as scripts in the package
      *