Read directory settings from rc file

The directory now reads settings from /etc/psnetrc.  Directory settings
are listed in the "Directory" section of the file.
Read router settings from /etc/psnetrc

The router no longer reads settings from multiple files.  Instead, it
reads its settings from the "Router" section of /etc/psnetrc, which is
the same file that psdird reads its settings from.  Settings can be
overriden on the command line.