- ns_put_rr function now accepts consts rrsets only
- fixed wrong TTL set in SOA copy
- removed a function move_rrset, to be replaced with RRSet function
  later.

- all serialize/deserialize functions should be moved here eventually.

- RRSet function removed altogether, it was not needed.

- find_rr_pos was used as an intersect operation.
- added flag to compare TTLs for intersection operation - I don't like
  this, other way would be to check if one of the TTLs is 0 and ignore
it then, but I doubt that would be transparent enough.

 - wrong if, no copy of NSEC3 nodes was made -> leaks.

 - node->new_node is thus obosolete.
 - since hattrie_dup made almost a full copy anyway, it's feasible to
   let the zone contents recreate the zone anew, with proper pointers.
(new node was used to set only parent pointer, others were reset anyway
in adjusting, all this will die in the new zone API, but at least like
this it's easier to maintain.)

- mm_realloc is now static, since it was only used in rr.c anyway.

- NSs in apex - some possibly problematic scenarios.
- CNAMEs - dtto

 - todo: Find file with __i386__ define or something similar
 - removed contst getter for rr rdata.
 - reused knot_rr_array_size function for size + META_SIZE like formulas