Merge branch 'master' into new_node

Conflicts:
	src/knot/dnssec/zone-sign.c
	src/knot/updates/ddns.c
	src/knot/updates/xfr-in.c
	src/knot/zone/node.c
	src/knot/zone/node.h
	src/knot/zone/semantic-check.c
	src/knot/zone/zone-contents.c
	src/knot/zone/zone-contents.h
	src/knot/zone/zone-create.c
	src/libknot/rrset.c
	tests-extra/tests/ddns/basic/test.py

Note: ddns/basic fails now, but I don't think it's caused by my merge
jutsu.