Add a license about estree

[sebmck]

Yep, I alluded to this in #44. The SpiderMonkey AST spec was published on MDN so it's probably under the license of Creative Commons Attribution-ShareAlike license as specified in About MDN. @dherman can possibly confirm or shed some light.

[sebmck]

@mikesherov Might be good to get a CLA too.

[mikesherov]

I'd prefer CC0, but CCAS is fine too.

Re: CLA, I'm ambivalent to needing one, but if we think it's a good idea, I can see about getting one. ESLint and jQuery both have fine language in theirs that we can be inspired by.

[sebmck]

I can see it potentially being an issue for a large company etc that wanted to adopt it.

[mikesherov]

Ok, then I'll look into it.

[jmm]

This would be a good thing to get resolved. Aside from building tooling around it there's also prose involved, with no clear license to use it elsewhere and contributions from non-members being merged without any indication about what license they're providing.

[mikesherov]

Would anyone be opposed to slapping MIT on this?

[RReverser]

@mikesherov I'm fine with it. But I believe the most important is to get agreement from @dherman or others people who worked on SpiderMonkey AST in the first place, as we basically forked their spec.

[theduke]

Bump.

Need a license on this.