This is a first step in implementing a configuration file for xlxd.
It supports reflector callsign, listening IP, and ambe transcoder IP.
It loads the configuration file from /xlxd/xlxd.config (unless
redefine at compile time).
It keeps backward compatibility with the command line parameters that
will override the values in the config file.
Gbp-Pq: Name 0006-Implement-configuration-file.patch