- Added debug message to ddns.

It is possible to use algorithm an certificate type mnemonics now.
This case concerns CERT, DS, DNSKEY and RRSIG types.

- First insert node's owner into lookup, then perform rest of the operations.

- Dname might be present somewhere else in RDATA.

- Code review helped.

NOTE: not completed

refs #2137

- Was causing wrong node->owner->node values and thus incomplete
  additional sections.

refs #2137

Coverity scan #989558 (Logically dead code)

- wire_pos in compression info structure was not initialized properly
  (was set to 0 instead of response->size) resulting in bogus
compression (it worked for simple records, but failed for larger ones,
if containing more than one name)
- fixed compilation warnings in debug messages.

Coverity scan #989558 (Logically dead code)

refs #2138

- Assert on line 419 in response.c was failing - added an extra check,
  so that DNAMEs with offets less than header size will not be inserted
to compression table. Seems to have fixed the issue, but I'm not sure if
I haven't broken something else. Please review.
- Reeanbled packet compression.