function on_loaded()
	{
		LEvent.unbind( LS.ResourcesManager, "end_loading_resources", on_loaded );
		if(on_complete)
			on_complete();
	}
Loads all the resources of all the nodes in this scene
it sends a signal to every node to get all the resources info
and load them in bulk using the ResourceManager

@method loadResources
@param {Function} on_complete called when the load of all the resources is complete