Ported libknot to new pkt API.

src/libknot/consts.h

src/libknot/dname.c

src/libknot/dnssec/sig0.c

src/libknot/edns.c

src/libknot/edns.h

src/libknot/libknot.h

src/libknot/nameserver/chaos.c

src/libknot/nameserver/chaos.h

src/libknot/nameserver/name-server.c

src/libknot/nameserver/name-server.h

src/libknot/packet/pkt.c

src/libknot/packet/pkt.h

src/libknot/rrset.c

src/libknot/rrset.h

src/libknot/tsig-op.c

src/libknot/tsig.c

src/libknot/updates/ddns.c

src/libknot/updates/ddns.h

src/libknot/updates/xfr-in.c

src/libknot/updates/xfr-in.h