Simplify

I took a very simple approach to this. So far it has seemed to work out pretty well for me here: https://github.com/slamdata/slamdata. There's probably a whole slew of bugs in here waiting to come out, but I thought this might be a nice start for a rewrite.

Please review/comment/suggest.
What do you mean? It's actually representing the `this` keyword in js. Though it's kind of confusing for it to have an `isMounted` field, so maybe that field should come out.