Conflicts:
	src/zoneparser/zoneparser.c

Refs #280

- zonec renamed to zoneparser
- src/zone/ renamed to src/zoneparser/
- zone loader and zone dump moved to dnslib

- Prefix zload for loader and zdump for dump.

Conflicts:
	src/zone/zone-load.c

Conflicts:
	src/zone/zone-load.c

- Added function dnslib_response_contains() to check if the
  response contains the given RRSet
- Modified functions dnslib_response_add_rrset_*() - added
  parameter for enabling checking of duplicates
- Modified nameserver functions accordingly
- Modified response tests to reflect the new API

refs #257

refs #277,#273

Conflicts:
	src/zone/zone-load.c

Conflicts:
	src/zone/zonec.c

Conflicts:
	Makefile

- If the found zone was last in canonical order and the QNAME
  was greater than the zone name, it returned the zone no matter
  if the QNAME belonged to the zone.
- Quick fix, would require more thorough testing and maybe complete
  change of the structure in which the zones are kept.

Closes #252

Refs #252