Build: clean up Makefile comments a bit
Build: clean up Makefile comments a bit

- Credit Andrew Ray, the author of the current Makefile.
- Remove inaccurate license line.
- Lwt is no longer an OASIS project.
- Remove redundant file name comment.

[skip ci]

ocsigen/lwt,c-cube/lwt,c-cube/lwt,rneswold/lwt,rneswold/lwt,rneswold/lwt,ocsigen/lwt,ocsigen/lwt,c-cube/lwt