It's possible for the debugger to be invoked from inside code wrapped in
a (quiet! ...) call. The debugger pauses Emacs in a broken state where
the functions locally rebound by quiet! (e.g. message, load-file,
write-region, etc) are never returned to their original definitions.
This attempts to reduce that probabilityby changing how quiet! silences
code. Rather than silencing them completely, they will be logged
to *Messages* but not displayed in the echo area.
Also, quiet! is now used less, where it isn't strictly needed (or where
inhibit-message is sufficient).
