* Implemented new editor-based debugger, which uses the standard

* Implemented new editor-based debugger, which uses the standard
debugger to generate its presentations (by means of new hooks in the
runtime system).  The debugger can be invoked manually by the command
`browse-continuation', or automatically by setting one of the
following variables true:

debug-on-evaluation-error	error during evaluation
debug-on-editor-error		editor error (user error)
debug-on-internal-error		editor bug

Normally `debug-on-evaluation-error' is true and the others are false.

* Controlification redone so that controlification of all ASCII
control characters is uniform.  Previously characters such as newline
and page were handled specially.  The net result of this is that
controlification of an ASCII control character has no effect.

* C-x C-c is now bound to a command which exits Scheme and returns to
the unix shell.

* All messages are cleared immediately after reading the first
character of a command key sequence.  This is similar to the action of
GNU Emacs, and prevents non-temporary messages from sticking around
for a long time.

* Dired now handles symbolic links specially, showing the file linked
to in the usual way.

* Bug fix in `clear-message': this procedure now preserves the
command-prompt; previously it was clearing both the message and the
command-prompt.

* Bug fix in "cterm": the `move-cursor!' operation must move the
cursor immediately if an update is not in effect.

* Bug fix in `revert-buffer': can't assume that the buffer being
reverted is current.

* Bug fix: `with-output-to-string' had incorrect indentation method.

* Bug fix: typo in dired sorting routine.