Fixes unexpanded wildcard appearance in Additional section.

- includes not finished yet

- Fixed DO flag setting.
- Fixed RDATA setting in OPT init. There was some weird problem
  with the allocated dummy RDATA. Using stack instead.
- Flags were not initialized.
- Fixed flag setting in kdig.

- OPT RR is now a normal RRSet.
- Server stores only some EDNS options.
  (Will be changed later back to whole RR.)
- Rewritten EDNS getters and setters to use normal RRSet.
  (Option manipulation not done yet.)
- Added helper function for getting RRSet TTL.

- 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.