Tests for server unit.
TAP protocol output.

- No epoll and master thread
- Workers are racing on recvfrom()
- Workers are natively blocked by recvfrom()
- Zero synchronisation overhead
- Presuming recfrom() is thread-safe

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).

Changed cute_start() to take more file names + passing these
  filenames from command line.

Was treating all nodes as delegation points.

Now answers 100% queries!

Documented TCP/UDP handlers and socket manager.
Cleanup of the socket manager APIs.

API consists of compulsory master thread routine and non-compulsory worker routine prototypes.

Conflicts:
	src/zone/zone-database.c

Zone nodes are inserted into zone data structure first, only
  marking delegation points and skipping their children.
All adjustments use zone data structure for lookup (speeds up
  delegation point adjusting significantly).
Showing progress of zone loading (list creation, zds filling,
  adjusting).

Delegation points are now adjusted while inserting the nodes into
  the zone data structure (zdb_insert_nodes_into_zds()) instead of
  during general adjustmen (zdb_adjust_zone()).
In non-apex zone nodes NS is not adjusted (all NSs in such nodes
  are considered to be delegations).
Nodes are inserted into the zone data structure before adjusting.
Adjusting of CNAMEs and Additional data is done using the hash
  table.

Note: Adjusting of the delegation points may still be too slow.

Fixed nameserver answering when part of name is found.

Returning REFUSED to queries for non-authoritative names.
Adding EDNS0 OPT RR only when client supports it.

Slightly modified log output.

The case when all zones are tried was not handled.

Added function zn_all_rrsets() and changed ns_put_answer() to
  distinguish between ANY and other QTYPEs.

Queries with no Question entry will get FORMERR as a reply now.
Fixed increasing the packet size to consider the OPT record
  (was increasing it for each question entry).

zn_add_referrer_node() - bad checking of return value from
  da_reserve() (returns positive integer if successfuly resized).

Zone node now keeps track of other nodes that hold some referrence
  to it (e.g. through CNAME or additional records).
Added function zn_add_referrer() to set referrer for given type.
Removed function zn_add_ref_cname() and its functionality merged to
  zn_add_ref().