Inject dependency rather than using new

[radu-matei]

https://github.com/radu-matei/websocket-manager/blob/master/samples/ChatApplication/ChatHandler.cs#L11

In one sample, a dependency needed for the handler is newed-up rather than injected using dependency injection. This should not be handled by the user of the library, but rather by the library itself:

        public ChatHandler(WebSocketConnectionManager webSocketConnectionManager) : base(webSocketConnectionManager, new ControllerMethodInvocationStrategy())
        {
            ((ControllerMethodInvocationStrategy)MethodInvocationStrategy).Controller = this;
        }

cc @Henry00IS