Kind inference

I have been working for longer than I care to admit on a significant refactoring of kind inference. I've just pushed it. It's a pretty big patch, which Richard and I have been discussing for some weeks. It validates, and fixes at least nine troublesome open tickets. But of course I could have made a mistake. Be vigilant. My: there will almost certainly be conflicts with your visible kind application patch, especially in tcInferApps. But that function has gotten substantially simpler in my patch so I don't think it'll be hard to fix things up. Phew! Simon