Fix Trac #43 again.
stream.lisp: o Remove the old code that was the first attempt at fixing issue #43. This was wrong. fd-stream.lisp: o Fix issue #43. Even if we have a string-buffer, we need to take into account any octets in the in-buffer (if it exists) that have not been processed. This happens if the in-buffer does not have enough octets at the end to form a complete character for the given encoding. o Some debugging prints added, but disabled.