Zone adjusting modifications + fixes.

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.