[plt-scheme] PLAI now in print

I'm writing to announce that my book, PLAI, is finally available IN
PRINT.  The paper version is a modestly-priced paperback.  (But, a
full electronic version will always remain on the Web, free of cost.)

Also, I noticed that some professors were choosing to extract just the
modules that fit their courses.  This was questionable under the
traditional copyright.  I have thus adopted the Creative Commons
by-nc-sa license, which permits "remixing" the work.

As always, the book is here:

http://www.cs.brown.edu/~sk/Publications/Books/ProgLangs/

I welcome all feedback.  Thanks for your support!

Shriram