Injection of stream options into websocket client

First of I'd like to say thank you for all your effort you've put into this. I really appreciate it. 

I've had the requirement to authenticate with a client side SSL certificate while connecting to a websocket server. This was not possible in the current master. I've added the possibility to inject stream options into the constructor of the websocket client. 

Additionally, I fixed a small mistake in the README.md: `$client->on("connected", ...)` => `$client->on("connect", ...)`.