get macaddress from ifconfig output for gnu/kfreebsd
implemented value_for_interface_and_label for freebsd
darwin netmask && macaddress specs
add netmask spec for gnu_k_free_bsd
add infiniband specs to linux
remove the most useless spec in the suite
add non infiniband specs to linux
add mtu specs for darwin
windows .value_for_interface_and_label
make these a little bit more readable