please add specific version listings in Release Notes

[Kieren Richard MacMillan]

Hello, development team:

Just a little request...

Since you are improving Lilypond so rapidly (which I appreciate more 
than I can tell you!), it often turns out that I am several versions 
behind, and can't tell what has been changed since what. If the release 
notes could be a little more specific than "New features in 2.1 since 
2.0", it might help those of us who can't keep up with 
SuperDeveloperMan and his sidekicks at the Hall of Scheme...  =)

Even just a parenthetical at the beginning of the line would be enough, 
e.g.,

     [v2.1.10] Default staff sizes are now scalable. There are two new 
mechanisms [...]

Thanks a million!
Kieren.