New feature: zeroconf networking by default, please test

[Andrew Jorgensen]

The old zeroconf package (I know we're using avahi-autoipd) would
setup a zeroconf address on an interface in addition to any configured
or dhcp address.  This worked fine for me.  If I understand correctly
the current approach is to configure a link-local address only if no
static address was given and dhcp fails.  There have been some
complaints about this not working well and I wonder if it might be
better to use the approach the zeroconf package used.