[plt-scheme] Change to setup-plt

On Mar  3, Eli Barzilay wrote:
> [...]

I just realized that this is exactly the kind of change that should
have a version bump so that planet packages can use that information.
I'll do that later tonight.

-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                  http://www.barzilay.org/                 Maze is Life!