Change-Id: I429b3833c5db9e78220beb1ea72980b557ba06c4

- The canonical domain name was not taken from the CNAME RRSet in
  zone, but from the one synthetized from the wildcard. This caused
  the node's owner to be different than the CNAME name.
- Added the case causing the cycling in to the example.com zone.

fixes #1313 @1h30m

- The AXFR-in processing function seems to work quite OK now,
  but needs extensive testing.
- Modified test zone file (shorter times).

refs #875 @1h45m

Fixes #823 @3h

Added check to zcompile.
Refs #713 #709 @40m

- Infinite loop replaced by several labels and gotos.
- This fixed problems with CNAME resolving related to closest
  enclosers saved in dname.node.
- Fixed DNSKEY adding - was not checking if the RRSet is there.

TODO: Try to refactor the answering code
TODO: Simplify DNSSEC records adding by marking the zone as signed
      / unsigned.

fixes #640

- Added sample zone file for example.com zone signed with NSEC3.

refs #425

- Edited to conform to zonesigner requirements.

When processing DNAME, the actual qname should be used instead of
  the one from the query (e.g. when after CNAME).
Saving the actual qname before stripping and using it in DNAME and
  wildcard processing.

There are probably multiple bugs, needs a lot of testing and
  revision of the algorithm.
However, it should mirror the current state of the flowchart
  (230910-my).

If all labels matched & the node is empty non-terminal, continue
  the search.
If some labels matched & the node has no wildcard node, return
  NXDOMAIN.

Empty non-terminals are created after creating the zone list and
  before inserting into ZDS. The algorithm is quite straightforward
  - for each node it finds a 'parent' node and creates all nodes
    'missing' between the parent and the node. Search for parent
    optimized by saving the last parent + jumping directly to zone
    apex if number of common labes is equal to size of the zone
    apex' owner name.

Added function zn_is_empty().
Skipping empty nodes when processing non-authoritative nodes.

Changed answering algorithm so that DNAME is checked before
  wildcard and zone apex.
  (See query-processing-flowchart-200910-2.png.)
Implemented CNAME from DNAME synthesis - quite dumb, with a lot of
  copying (because of ldns).

GLUEs found in authoritative data are extracted, those found in
  other delegations are ignored (out-of-bailiwick).
Adjusting of zone node ends after it finds CNAME or delegation.

Zone adjustments now add A/AAAA references for SRV records.
Nameserver adds these records to Additional section.
Modified zone node flags (now 16 bit).

ns_put_glues() now copies the glues one by one and if a wildcard
  is encountered, the RR is copied and owner is replaced by name
  found by searching through the NS RRs in Authority section.
  (This approach should be faster than using the zn_get_glue()
   method for each name and type as in that case we would need to
   always iterate through the Authority section and in each
   iteration iterate over the glue records.)

zn_get_glue() now processes wildcard glue records. (The function
  however is not used right now.)

Fix in zdb_process_nonauth() (should not free the list of names).
Changed zdb_dname_list_contains() to zdb_dname_list_find() which
  returns the found name. Not utilized now. (May change back later)

Function ns_follow_cname() generalized to put RRs to given section.

Once again putting RRSets to packet separated into generic function
  ns_put_rrset(), now with wildcard processing.

ns_put_additional() now puts all additional RRSets into the packet,
  not only for given type (either way was iterating through the
  whole Answer section).
ns_put_additional() now processes CNAMEs.

zdb_adjust_additional() now saves also pointer to node with CNAME
  record, to be used in answering.

Structure zn_ar_rrsets modified to be able to hold pointer to CNAME
  node. TODO: consider using union to save space.

Added zn_add_ref_cname() to add CNAME additional reference.
  TODO: is copy-pasted from zn_add_ref(), consider refactoring.

Was not marking the node as CNAME if the canonical name node was
  not present.
Was not copying the last CNAME record in chain if the next
  canonical name was not present.

Query processing changed to accomodate proper wildcard processing
  (see the new flowchart). Used one ugly goto, but cannot think
  about any workaround right now.

If a wildcard is encountered when getting answers (or resolving
  CNAME chain), the corresponding RRs are now copied into the
  response packet and saved to a list of copied RRs for further
  deallocation.

Removed ns_put_rrset(), as in case of answers we needed to perform
  the wildcard checks.

Fix: Freeing of the copied qname in ns_answer().

zdb_create_list() was inserting the nodes in reverse order
  (ldns_rr_list_pop_rrset() pops LAST RRSet, not first!).

Empty response was used for responding to all queries, though
  it lacked data copied from the query. Now copies ID, Question,
  and RD bit if a query is given.

Added a lot of debug ouput in zdb.
Added delegation point and glue A records to example zone file.

ns_create_response() divided into ns_create_empty_response()
  (empty response may be used as an error response) and
  ns_fill_response().
Added another sample zone as ldns had problems parsing the bogus25
  zone.