Add support for KGS

[artasparks]

Now that the KGS protocol has been opened up, now is the chance to make Glift work with KGS.

The protocol: https://www.gokgs.com/help/protocol.html
The mailing list: https://groups.google.com/forum/#!forum/kgs-client-coding

[kadoban]

I have started a new controller to be used by my own KGS client at kadoban/glift/tree/develop if anyone wants to keep tabs. It's nowhere near done and the actual client part I'm not publicly sharing yet.

I'll do PRs when things are in a more stable state of course. I'll set up a todo-list somewhere around here somewhere soon as well.