[plt-scheme] Choosing a language version

This is just a thought, but something like a "feature table", roughly  
outlining what is included in each language might be helpful to  
newcomers.

===
Gregory Woodhouse
gregory.woodhouse at sbcglobal.net

"And the end of all our exploring
will be to arrive where we started
And know the place for the first time"
-- T.S. Eliot