Added if_active event to mdns_core.
Fixed is_empty event. Serious brainfart ongoing (is_empty utility + is_empty event = not win).
Made autodiscovery happen once a minute + added debug message.
Implemented OSPF tree changes based on if_active from mdns_core.
Added activity tracking to the testcase.
Merge branch 'vancouver' of https://github.com/fingon/hnet-core into vancouver