Find a cross-platform solution for DNS-SD (bonjour)

[oleksandr]

Current package we're using does not work under Linux (with Avahi/DNS-SD compatibility layer). More tests need to be done on Windows.

[oleksandr]

As a result I've impemented oleksandr/bonjour package (pure Go, no C/C++ dependencies). The discovery is fine, but registration requires a bit more work.