[plt-scheme] Servlet2 and standalone.ss

>    1. Are you using HTDP
>      yes -> Choose one of the teaching langauge
>    2. Are you following another book
>        yes -> SICP, TAPL, etc.
>    3. Recommend "Pretty Big Scheme"

This is a REALLY GOOD IDEA.  After the (human)
language choice, present the following:

If you are using DrScheme in conjunction with a textbook,
please select it below:

- HTDP
- Fixnum
- SICP
- EOPL
- PLAI
...

For each one, make some reasonable choice (ie, even though
there is no SICP language level, choose something that is
reasonable for SICP).  If they choose one of these, don't show
the current default (the language choice menu).

The default in the second menu should be Pretty Big.

Of course, if they answer something other than HtDP, we also
send them back to the first menu until they choose HtDP. <-;

Shriram