Removed zone lookup from config, as it's being removed from the global conf and moved directly to the zone data.

refs #1976

Missing RCU unlock + replaced numbers by error codes.

refs #1976

refs #1976

Added some missing read locks.
TODO: may deadlock somewhere, some functions still find zone from zonedb
and may corrupt new reloaded zone instead of zone the transfer was started

refs #1976

refs #1976

- Wrong flag was used.
- Added some detailed debug messages (may be removed later).

refs #1952 @3h

- Added more detailed debug messages to zone-diff

+ Some minor fixes.

refs #1949

refs #1949

- Added KNOT(D)_ENODIFF, which is now being returned when no zone diff could be produced.
- if new zone has lower serial than old zone, return KNOT_ERANGE
- Proper comparison of serials added.

Refs #1949

Refs #1949

- Replaced error codes (KNOT -> KNOTD)

Refs #1949

- To zones.c
- Also saves changesets to journal, journal reference is taken from the first zone.

refs #1946

Resulted in some event duplication.

refs #1926 @20m

Now everywhere the server tries to respond with the whole Question
section. When it is not possible, it at least copies the ID and
flags.

refs #1935 @30m

Not only the name but also the algorithm must be checked.

refs #1933 @10m

TSIG is now detected while parsing the RR sections. If it is
there, it is stored in the packet. This also allows for checking
whether TSIG is not in a forbidden place, or whether there is
only one TSIG, etc.

Also removed all TSIG recognition code from other parts of the
server. Not needed anymore.

refs #1522 @1h

Old: [AI]XFR of 'ZONE/(IN|OUT)' ...
New: (Incoming|Outgoing) [AI]XFR of 'ZONE' ...

refs #1912

refs #1912

refs #1918 @20m

refs #1918 @15m

refs #1838

refs #1880