#174 - Send WebSocket messages async

PlayWallPlugins/PlayWallPluginWebAPI/src/main/scala/de/tobias/playpad/plugin/api/websocket/WebSocketHandler.scala

@@ -54,7 +54,7 @@ class WebSocketHandler {
 
 		sessions.stream()
 			.filter(session => session.isOpen)
-			.forEach(session => session.getRemote.sendString(payload))
+			.forEach(session => session.getRemote.sendStringByFuture(payload))
 	}
 }