@dmiller-nmap The build fails due to travis not running python3 on zenmap, ncat and ndif. Otherwise, the code builds just fine.

Hello,
Do you have any plans regarding this PR? I'm asking because many distributions (openSUSE [1], Fedora [2], Debian [3], Ubuntu [4], ...) are currently in the process of transition from Python 2 to Python 3 as a default. Because of that, I guess that it's a high time to switch to Python 3 for zenmap/ndiff/ncat too.

Thanks in advance for moving this forward!

[1] https://lists.opensuse.org/opensuse-factory/2017-06/msg00740.html
[2] https://fedoraproject.org/wiki/FinalizingFedoraSwitchtoPython3
[3] https://lists.debian.org/debian-python/2014/05/msg00037.html
[4] https://wiki.ubuntu.com/Python/3