Add an option to support disabling perMessageDeflate

[joewood]

Azure AppService's support for websockets requires disabling perMessageDeflate extension to websockets. This is an option in the constructor to the WebSocketLibrary. I added the following line to fix this:

this.socketServer = new WebSocketLib.Server({ path: this.path, server, perMessageDeflate: false });

Could you add a configuration option for this? Would you accept pull requests?

[afrokick]

@joewood of course, any PR are welcome!