- knot_zonedb_remove_zone() now returns the removed zone and does
  not deallocate it in any case.

- Server was sending responses larger than 512B even if client did
  not advertise EDNS.
- Now using the given buffer for the packet's wireformat - should
  avoid some unnecessary mallocs.
- Setting TC bit in wireformat was missing.

+ removed some unused code.

Improved parser for more checks and defined behavior if iface/remote has no addresses. Allows keywords any/all etc. in iface/remote name.

To do: How to expire zone? Currently, zone is still served after expiration.