Add support for Avahi/Zeroconf auto-discovery

[vranki]

Currently user needs to know the IP address for computer running ExtPlane. This is annoying sometimes if IP can change.
Add support for Avahi (aka ZeroConf) protocol which would allow automatic discovery of the service.

Do it in platform independent way if possible.. I don't know if there is a common library to do it.

[dankrusi]

I added hostname support a while ago (ie flightsim1.local, MYWINDOWSPC, flightsim.domain.com), which should theoretically allow for moving IPs. This might be sufficient for most people...?

[Dimsday]

http://blog.shahada.abubakar.net/post/linux-udp-network-client-library-for-x-plane-10-and-11
See: BECN

[vranki]

Thanks, this is cool. We could actually use this UDP networking interface to do limited pluginless ExtPlane and/or use UDP for high performance per-frame updates.