[racket] replacing readline (Was: Can't delete chars in racket's terminal interpreter)

If some undergrad wants a fun one-week project to start the summer...  
Write a replacement for "readline" that can be used by the Racket 
command-line REPL.

Two reasons: (1) avoid license and not-working-out-of-the-box issues 
with "readline"; (2) you can do cooler things, like auto-indent, 
paren-matching, and up/down cursor that works in whatever portion of the 
terminal the text occupies.

This can probably be layered atop 
"http://www.neilvandyke.org/racket-charterm/".  If you find you need 
some low-level feature not in that library, such as some additional 
reporting of terminal characteristics or state, I could probably be 
persuaded to add it.

Neil V.