Allow phyint enable syntax, add -N option to disable all interfaces by default

Provides the same feature as pimd uses.

Signed-off-by: Joseph Gooch <mrwizard@dok.org>
Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
Add support for -M, --missing-ok option for better use with dynamic interfaces

Signed-off-by: Joseph Gooch <mrwizard@dok.org>
Signed-off-by: Joachim Nilsson <troglobit@gmail.com>