Cope with different versions of netcat

Issue #1 wontfix
David North
repo owner created an issue

Following on from pull request #1, eximunit should try and cope gracefully with netcat-traditional and netcat6. I should also look at workarounds for the lack of -e and -c switches on netcat-openbsd.

Maybe try and cut out netcat altogether and use the subprocess module and our own sockets?