Bad source size counting. Still needs polishing.

Used traverse_rdata() function. Still needs some polising and
more refactoring (together with the rr_from_wire() function.

First draft. Requires some optimizations and testing.

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.