Expand copyright to include babylon/acorn authors, add AUTHORS file

[alangpierce]

No description provided.

[alangpierce]

@kittens does this seem like a reasonable way to do it? The copyright is a bit complex I guess, and it's a little weird in that Acorn explicitly lists all contributors and Babel seems to be completely under your name and doesn't track contributors as far as I can tell. Fortunately it's all the same license.

[sebmck]

You just need to put the LICENSE and AUTHORS file into the sucrase-babylon folder and you're fine.

[alangpierce]

Ah, I see. I was planning on integrating it into the rest of the code pretty soon anyway; it's just tech debt that it's still its own top-level folder, rather than any significant attempt at keeping it a coherent fork or independent module. Does the top-level license approach make sense to you given that interpretation? Happy to add LICENSE and AUTHORS in the subdirectory regardless if you think that's better.