Todo:
* Private key file parsing use io.Reader (or the like) - NewReader, NewWriter?
* Parsing from strings, going with goyacc and .cz lexer?
* encoding NSEC3/NSEC bitmaps, DEcoding works
* AXFR/IXFR with TSIG validation
* Failed Xfr triggers nil error?

Issues:
* Check the network order, it works now, but this is on Intel??
* Make the testsuite work with public DNS servers
* pack/Unpack smaller. EDNS 'n stuff can be folded in

Examples:
* Test impl of nameserver, with a small zone, 1 KSK and online  signing