Copyright Problem with wording in README

[JoesCat]

Hi Raph,
Please update your README file.

For users that don't understand what is written in your README file, some developers will take it to imply you mean to say that they can declare their code as MIT - here is a solid example:
fontforge/libspiro#16

[raphlinus]

Seems clear enough to me, but I'll take a PR to clarify it further.

[nanjizal]

Raph please remove your hxSpiro2019 fork of my lib as I do not wish to release that library as GPL.
https://github.com/raphlinus/hxSpiro2019
I prefer to have the way clear of similar code style if I decide to attempt a clean MIT port of spiro in the future although that's not currently likely, sorry as we discussed the intention of the 2019/20 versions were to move to MIT but seems derivative was an oversight the intricacies of when a port is derivative are likely complex, it is just simpler to remove than have three unmaintained GPL versions especially as 2019 has no example tests yet anyway ( your fork was behind master and I don't think had docs ).

hxSpiro will remain GPL and online.