fix(server): properly close flash transport

lib/server.js

@@ -216,6 +216,11 @@ var start = function(injector, config, launcher, globalEmitter, preprocess, file
       // shutdown the server...
       webServer.close(removeAllListeners);
 
+      // shutdown socket.io flash transport, if defined
+      if (socketServer.flashPolicyServer) {
+        socketServer.flashPolicyServer.close();
+      }
+
       // ...but don't wait forever on webServer.close() because
       // pending client connections prevent it from closing.
       setTimeout(removeAllListeners, webServerCloseTimeout);