Merge pull request #3 from stephen-soltesz/master

First draft of DONAR-workalike for mlab_utility
Merge pull request #4 from stephen-soltesz/master

prepare for production use of 'donar' replacement.
Merge branch 'master', remote branch 'upstream/master'
install donar.txt in /etc/ for access by other users
handle NS requests for sub-zone