don't report radio link every second, even when debugging packetradio.
every 30sec is enough.
close interface if we get ENETUNREACH or ENETDOWN instead of
complaining about it endlessly.
improve handling of network interfaces marked down:
close if down, report an error otherwise.
Treat empty filehash the same as NULL
Merge remote branch 'origin/development' into meshextender
back out segfaulting changes to interface down error message
suppression