[Ironruby-core] Contributor's agreement

[John Lam (CLR)]

> My vote: Keep 'em both and add another line at the very bottom of the
> second page in 6pt sub-script that states "I can't believe we're actually
> going through with this. ~Bill G."

:)

I put up that doc as-is since folks signing the agreement will do so via some kind of web site (details to come). I'll take it down once we have the right mechanisms in place.

-John