Extend WampSessionClient ctor with authenticator param

Add overloaded CreateChannel method to IWampChannelFactory
Add JSON and MsgPack channels creation methods to DefaultWampChannelFactory
It's more changes as I think but it works.
I'm glad to participate this project and wait for your comments for this commit.
Can you please use the extra parameter too?
Usage: 
var myData = extra.OriginalValue.Deserialize<MyClass>();