Todo:
* wildcards, in sig gen, sig checking
* Private key file parsing use io.Reader (or the like) - NewReader, NewWriter?
* Tsig generation for replies (request MAC)
* nsupdate, it's there except for the names

Longer term:
* Parsing from strings, going with goyacc and own lexer
* NSEC and nsec3 closest encloser helper functions
* pack/Unpack smaller. EDNS 'n stuff can be folded in
* Test impl of nameserver, with a small zone, 1 KSK and online  signing

Issues:
* Check the network order, it works now, but this is on Intel??
* Make the testsuite work with public DNS servers