File Release Notes and Changelog

Minor update. Mlpost should now compile and be usable on most configurations.

- Melt compiles with Ocamlbuild 3.10.0 even with the main Makefile.
- All combinations of -no-mlpost or -no-ocamlbuild options should work.
You still have to add "-I +mlpost" yourself if you compiled Melt with Mlpost
but use the -no-mlpost option.
- The -no-mlpost option is set by default if Melt was compiled without Mlpost.