cov#1165386

cov#1165387

cov#1168292

cov#1169882

cov#1165390

UPDATE forwarding fixed to work with the current API

I'd like to run `tests-extra` as part of the nightly tests soon, so we can root out the old test cases.
UPDATE forwarding was disabled until now, I enabled it to work with the current API until it is reworked.

Remove Integrity Check

This is going to be reworked with the new response processing API,
but it needs to be working for the tests.

* origin/merge-nameserver-server:
  evsched: updated comments and renamed some attributes
  evsched: add missing header
  evsched: removed deprecated evqueue and streamlined the API
  remove void comments
  minor formating fixes
  utils: renamed knot_serial_compare and added headers
  zone: common API for controlling zone timers
  nameserver: Merged nameserver_t -> server_t
  nameserver: removed redundant attributes

zone: use just one free function

Fixes broken build on some distributions.

* events now carry pointer to their scheduler
* no event types, events are simple callbacks
* removed unused or deprecated stuff
* bugfix: zone never expired since expire was initialized on create
* bugfix: race condition on rescheduling events
  - there is always some time between cancel and schedule
  - if two threads run run past the cancel and then race for schedule,
    they may rarely schedule an event two times
  - this is hard to deal with unless we place a lock on the zone
    operations, therefore each schedule checks heap if the event is not
    already scheduled and if it is, it replaces the old instance

Several NSEC(3)-related bugs fixed

1. When replying NODATA response from empty non-terminals, NSECs for NXDOMAIN have to be added instead of NSECs for NODATA. (Does not apply for NSEC3.) This was not handled in the rewritten query processing.
2. When adding RRSet to node, do not increase RRSet count of that node, if the RRSet is empty and contains only RRSIGs. Such RRSet was counted and it resulted in wrong behaviour when RRSet was removed but its RRSIG remained in the zone. (Note that in current implementation the RRSet count in node reflects only RRSets directly in the node, i.e. it does not count RRSIGs).
3. In some cases, NSEC3 records were generated for empty non-terminals that were subsequently deleted after applying the DNSSEC changeset. See issue #210 for description and solution.

Remove the confusion of regular and deep free. The zone contents is
always freed - the caller can unset it before calling free, if the
content is re-associated to a different zone.

issue #205

* zone timers are frozen before zonedb reconfigure
* zone timers are rescheduled after zonedb is reconfigured & published

refs #209
fixes #202

Conflicts:
	src/knot/nameserver/name-server.c
	src/knot/nameserver/update.c
	src/knot/zone/zonedb.c

* removed redundant attributes
* removed unused parameter occurences
* moved related functions to appropriate files
* evsched has now context (server)
* zone does not point to server
* zone event planning is still in the zone loading and requires server #209

libknot: move debug API into knots

This simple change just move API for debugging from libknot into shared code static library.

closes #204

Merge zone_t and zonedata_t

Merges public and private API for zones, resulting in new private API.