insecure  delegation  ents and ...

- fixes #1289
- optout fixes 
- new axfr tool with stable output 'saxfr'
- two new tests 'axfr' and 'ent-unsigned-delegation'
- one modified test 'ent-axfr', use new axfr tool
- fixes AXFR output of mydns and opendbx backend
- and some other nits...