check the HTTP response status code and headers for websocket client

[tokers]

Hello!

Recently I'm working on developing some features based on this library. However, it seems that the websocket.client doest not check the status code, headers when handshaking. This may need to be strengthened. Is there any plan for this?

[agentzh]

@tokers Pull requests welcome :)

[tokers]

@agentzh OK, I will try :)