Refactor LICENSE-THIRD-PARTY.md (#2469)
Refactor LICENSE-THIRD-PARTY.md (#2469)

Regroup embedded or derived-from projects by license type, with each
license text reproduced only once. I think this makes this file much
more readable, shorter, and easier to see at a glance exactly which
parts are covered by which compatible licenses.
lgritz/oiio,OpenImageIO/oiio,OpenImageIO/oiio,lgritz/oiio,OpenImageIO/oiio,lgritz/oiio,OpenImageIO/oiio,lgritz/oiio