ssh-proxy.scm: Make it work with new Guile-SSH API.

* proxies/ssh-proxy/ssh-proxy.scm: Make it work with new Guile-SSH
  API.
Use the standard logger provided by GNU Guile.

* common/proxy.scm: Use the standard logger provided by GNU Guile.
  (log-error, log-info, log-debug): Remove.
  (proxy-log-msg): New procedure.
* lazycat-daemon/lazycatd.scm: Likewise.
  (log-debug): Remove.
  (setup-logging, shutdown-logging): New procedures.
* proxies/ssh-proxy/ssh-proxy.scm,
  proxies/tcp-proxy/tcp-proxy.scm, ui/gtk/lazy-gtk-cat.scm:
  Likewise.
lazycat-daemon/server.c: Rename to lazycat-daemon.c

* lazycat-daemon/server.c: Rename to lazycat-daemon.c
* lazycat-daemon/Makefile.am (lazycat_daemon_SOURCES): Update.
* lazycat-daemon/Makefile.in: Update.
lazycat-daemon/lazycatd.scm: Fix two bugs.

* lazycat-daemon/lazycatd.scm (setup-logging, run): Fix two bugs:
  tell the logger don't use stderr if the daemon is running in
  detached mode.  Open "/dev/null" as stdout and stderr after
  closing these ports to prevent `with-output-to-string' from
  restoring closed ports.