Add types

[azdavis]

Hi, cool project. I found it a bit hard to follow the types in the reference code, so I tried adding type annotations from what I could discern was the intent.

There were a few places where I wasn't sure where the boundary was for assuming optional things to be non-optional; I made that explicit with _unwrap.

I also

• replaced unused vars with _
• put most imports at the top
• used tuples instead of lists in one place( I think lists were used so it was easier to mutate, so I made a helper function to return a new tuple instead)
• use a Conflict enum
• use dataclasses with labeled fields instead of tuples

I put this patch into the public domain so that the project may remain entirely in the public domain.

Testing

All tests passed.

[bramcohen]

This is now conflicting because of bug fixes which were applied. It would also be good to squash it down and have fewer individual commits. But the general clean up is good.

[azdavis]

Ok, I rebased and squashed. All tests pass.