Extended RCODE is one 12-bit number. Until now it was not only
handled separately for old and new RCODEs, but it was also
interpreted wrong.

Unified RCODE processing - it's represented by only one number and
writing into the packet takes place at the end of query processing.

refs #300

fix LP signing

See merge request !293

persistent timers in storage subdirectory

See merge request !292

All data in server are kept in canonical format after recent
changes.The flag is no longer needed.

Existing code didn't recognize case sensitive RR types (LP),
which caused creation of invalid signatures.

RDATA lowercase

Some more tests would be handy, will add next week.

See merge request !288

Code cleanup

See merge request !290

EDNS fixes

- Fixed interpretation of Extended RCODE (was not joining the normal and extended RCODE fields).
- Modified output of Extended RCODE in utilities.
- If BADVERS is returned, return minimal error response. (No Answer)

See merge request !289

- Test changing case in different types and even adding a duplicate
  record that differs only in lettercase in RDATA.
- Also, test changing case in NSEC's next domain name. Should result
  in resign, but that doesn't happen right now.