This adds a new option in the aprsd.conf [DEFAULT] section
that denotes who is the callsign that officially owns this APRSD
instance. This will be used for sending the instance info to the
registry. It's useful when the callsign used by the instance is
something useful on the APRS network, which isn't necessarily the
same as the person that owns it.
This patch includes a completely reworked client structure.
There is now only 1 client object, that loads the appropriate
drivers. The drivers are fake, aprsis and tcpkiss.
The TCPKISS client was written from scratch to avoid using asyncio.
Asyncion is nothing but a pain in the ass.
