* Support NetBSD 7.1+ style ifconfig -a output
network facts on NetBSD after 7.1 cvs would fail
because of format changes in 'ifconfig -a' output.
update code to support new and old format.
add unit tests for both based on
examples from Bruce V Chiarelli.
* wrap use of interfaces.keys() in list() for py3 compat
* sort interface ids for stability
