* Change `environment-link-name' to call `->environment' on its two

* Change `environment-link-name' to call `->environment' on its two
environment arguments.

* Move `vector-binary-search' to the global environment.  Fix a bug in
it -- a confusion between the < used for comparing integers, and that
for comparing keys.

* New variable `load/suppress-loading-message?' prevents the file
loader from printing the "loading -- done" messages.

* Implement `pathname-relative?' which accepts two pathnames; if the
second has a directory part which is a "prefix" of the first, this
returns a copy of the first pathname with the "prefix" removed.
Example:

    (pathname-relative? (->pathname "/usr/bin")
			(->pathname "/usr/"))
	   ==> #[pathname 5 "bin"]