Changes since version 0.22:

There are now two GUI systems available. There is the standard MrEd GUI,
and there is also a system for using a Tcl GUI from CLISP (in Common Lisp).

General clean-up and minor bug fixing.

No more chain-loading of source files.

Support for clean compiling in GCL and CLISP are now provided in compile.lsp
and Makefile. When compiled, GCL and CLISP typically run twice as fast as
MzScheme.

The C preprocessing hack in config.lsp no longer interferes with the
Lisp editing mode in Emacs.

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The CLISP/Tcl GUI isn't quite as capable as the MrEd GUI. With the MrEd GUI,
you can type commands at the MrEd console while the GUI is up, and MrEd can
respond to them immediately. This allows you to run the animation sequence
in MrEd just by typing "(show-gui) (g)". If you try the same thing in
CLISP/Tcl, the "(g)" never gets heard by CLISP because all its I/O
resources are dedicated to communicating with the Tcl window. This might be
fixable in a future revision by using non-blocking I/O commands to poll both
the input channel from the Tcl process, and the user's typed input.

Also, even when CLISP is compiled, the Tcl GUI runs much slower than the
MrEd GUI. For instance, you can do smooth rotations on two atoms, but not
on ten atoms.

So those are the things that aren't too great about the Tcl GUI. What _is_
good about the Tcl GUI is that it compelled me to find out which parts of
the GUI code are implementation-specific (those parts are in the gui-2.*
files) and in both cases, it amounts to about 350 lines of Scheme/Lisp/Tcl.
Presumably, one could write GUIs for STk and gcl-tk also in about 350 lines
each.