This renames the method object in `defmethod`s to `this` and adds
detection for the `set-time!` and `time-elapsed?` macros.
Definitely my biggest PR yet...
The only interesting one is `collide-hash`, which is untested.
The other two are very likely unused. I skipped the annoying code in
`collide-probe` because it's not used and the same as jak 1.