[m-dev.] Renaming the NEWS file -> NEWS.md

[Julien Fischer]

Hi,

Since the Mercury repostitory is currently hosted on github, I have been
considering renaming the NEWS file -> NEWS.md and tweaking the
markdown** so that it is github flavoured.  Doing this means that when
browsing the repository on github that the NEWS file would be nicely 
formatted.

Are there any objections to doing this?

Julien.

(** theoretically the NEWS file should already be markdown, but
what some parts of it are in practice is anybody's guess.)