[plt-scheme] ajax and plt

We have a full, working compiler from Scheme to JavaScript for
Beginner and Intermediate Scheme plus the World framework for
interaction.  The compiler is self-hosting.  We are working on
plugging the generated code into other contexts such as mashups.

While the compiler is available, we aren't interested in supporting it
right now, as we're integrating it into a much larger framework.  We
are targeting a preliminary release of the whole framework by the end
of this summer, if not sooner.

I'm happy to try to answer questions.

Shriram