[plt-scheme] Tip: installing PLAI Scheme in DrScheme 4.2

I could not install PLAI Scheme using (require (planet plai/plai:1:3))
in a freshly compiled DrScheme 4.2 under the default Memory Limit of
128 Megabytes, but succeeded after setting it to "Unlimited" (I did
not try other values to see whether they worked).

I followed the instructions at [1], and got an "Evaluation Terminated"
dialog with the message "The program ran out of memory". After that,
further attempts at installing PLAI Scheme apparently worked but then
trying to run programs using PLAI tests failed with a message
regarding something already defined (sorry I did not capture that
message), so it seems the memory error left the PLAI installation in
some invalid state.

[1] http://www.cs.brown.edu/~sk/Publications/Books/ProgLangs/2007-04-26/

Removing DrScheme altogether, reinstalling it with ./configure, make
and make install and lifting the memory limit before doing (require
(planet plai/plai:1:3)) worked fine.

This machine is running Ubuntu 8.04.2 on an AMD 64 CPU.

Suggestion: add this tip about the memory setting to the instructions at [1].

Cheers,

Luciano