Relicense under trio MIT/Apache-2.0/Zlib

[madsmtm]

I'd also like to remove the copyright notice from the MIT license (see https://github.com/rust-lang/rust/commit/2a8807e889a43c6b89eb6f2736907afa87ae592f).

Upstream issues:

• https://github.com/SSheldon/rust-objc-foundation/issues/5
• https://github.com/SSheldon/rust-objc-id/issues/3
• https://github.com/SSheldon/rust-objc-exception/issues/2

Will probably need permission from (won't tag most of them yet):

• [x] @madsmtm
• [ ] @SSheldon
• [ ] @jrmuizel
  • https://github.com/madsmtm/objc/commit/2f906ee24ffbaead6e18e1d573e2de5865e19b8f
  • https://github.com/madsmtm/objc/commit/28a719f2edfe494ce4da9a0f841fac7d5c9f2498
• [ ] @alexbool
  • https://github.com/madsmtm/objc/commit/fa7ca43b862861dd1cd000d7ad01e6e0266cda13
  • https://github.com/madsmtm/objc/commit/b7dfa8f65859dce86d22d3981663d8628e6db304
• [ ] @bvssvni
  • https://github.com/madsmtm/objc/commit/b417a8c933c6a80f233476fac8215f4029973127
• [ ] @mehcode
  • https://github.com/madsmtm/objc/commit/d2176d1cf7632c9e49e6f9a7e563fe7f6d96f8c2
• [ ] @pcwalton
  • https://github.com/madsmtm/objc/commit/90ff608ecff82dbd2770bb4aa30f6c4745092700
• [ ] @burtonageo
  • https://github.com/madsmtm/objc/commit/e0a0547ec780974b8ce2ecc5a7a76b26a1ca4f5e
  • https://github.com/madsmtm/objc/commit/70c6d1ae6e059b6d042de09af47f3d1a1d74df81
• [ ] @syntheorem
  • https://github.com/madsmtm/objc/commit/5cd5c5b67c532da2723b2bab814ec23383d79bbc
• [ ] @ddrmanxbxfr
  • https://github.com/madsmtm/objc/commit/1c3f1027ae3da927480b92cf65e191e541939f0d
• [ ] @waywardmonkeys
  • https://github.com/madsmtm/objc/commit/e8f79d8c98eb484ccfb1923ca6e238ac333b8c14
  • https://github.com/madsmtm/objc/commit/d8e1c602450b721dc8ca59164c6e693f8d971940
  • https://github.com/madsmtm/objc/commit/642ea4a4a5853a21b55b05c34832a5f1bb1af61c
• [ ] @ngrewe
  • https://github.com/madsmtm/objc/commit/7a7da425d3729dc15685f42d4d2f6a1ad366f5a8
  • https://github.com/madsmtm/objc/commit/4ff9a8b03a35b07162859ce3af99d3abddaf9f48
• [ ] @codesmythe
  • https://github.com/madsmtm/objc/commit/0b098199138858784aede03432b1a847491d005a
  • https://github.com/madsmtm/objc/commit/54a15a3ed82015604d411fc67ad6249690c7005a
• [ ] @kvark
  • https://github.com/madsmtm/objc/commit/c86ad3a52984461fc5c63980d12e8ceed847854c
• [ ] @frewsxcv
  • https://github.com/madsmtm/objc/commit/5fd52e876b010dd1a6bcf06bb9ae6c947ed84e4d
• [ ] @jdm
  • https://github.com/madsmtm/objc/commit/12109dc53ee20e1f4547b0bbba3fadc4c906c523
• [ ] Others whose changes have been added after this issue was created.

[Lokathor]

If you're going to re-license, might I cheekily suggest that you also include the Zlib license as an option? The main difference from MIT is that you don't need to include the license text with compiled copies. SDL2 uses the Zlib license, I think it's quite nice for libraries to use.

[madsmtm]

Fine by me, still need a response from @SSheldon on this before moving forwards though

[amodm]

~~@madsmtm, I read @SSheldon's comment here as confirmation that he's ok with at least the licensing under MIT+Apache.~~

~~Are you awaiting a more explicit confirmation? Or awaiting Zlib's one? If it's the latter, can you at least proceed forward with the dual licensing?~~

~~And thanks for keeping this crate moving forward, and building upon @SSheldon's already fantastic work.~~

EDIT: never mind, I realise that that comment was in reply to Josh. @SSheldon, can you please provide a closure on this either way? It would be useful to have clarity on the licensing.