Add README.md

A small markdown README for GitHub users; points them to
the right README and the website and RT tracker.
RT 2517: Various typo's.

Many of these were already fixed, this catches the last
few that were missed.
RT 2517: Various typo's.
Reviewed-by: Emilia Kasper

Many of these were already fixed, this catches the last
few that were missed.
Undo 77bf69dced875200f6f0e385a4a270298f8d3c45

Not approved; mistakenly pushed commit that added README.md
Merge branch 'master' of git.openssl.org:openssl