- close stdout and stderr and reopen then as /dev/null when running as

- close stdout and stderr and reopen then as /dev/null when running as
a daemon. This prevents library functions (such as getopt) stuffing up
our protocol stream when errors are detected.

- defer the error message from the options parsing until after the
socket is multiplexed. This allows clients sending new options which
the remote server doesn't understand to get a sensible error message.