Restart tests

Review changes to the testing framework, please.

See merge request !247

- pending: Storing into journal ...
- I'll probably purge the changeset list in the future and merge all the
  incoming changes into one change ... but that will take time

Conflicts:
	Knot.files
	src/knot/nameserver/update.c
	src/knot/zone/zone-load.c
	src/knot/zone/zone.c
	src/knot/zone/zone.h

dnssec: no diff on initial load

The zone contents is empty on first load, therefore ixfr-from-differences failed to write the changes to the journal.

- tests adjusted