v4.0.0

• Change to a more typesafe options interface.

Instead of using a dictionary, it is now recommended you use a set of SocketIOClientOption.

let socket = SocketIOClient(socketURL: "", opts: ["log": true, "nsp": "/swift"])

Now becomes

let socket = SocketIOClient(socketURL: "", options: [.Log(true), .Nsp("/swift")])