set loopback to default network interface, improved simulation layout
set loopback to default network interface, improved simulation layout

arurke/contiki,MohamedSeliem/contiki,arurke/contiki,bluerover/6lbr,bluerover/6lbr,MohamedSeliem/contiki,MohamedSeliem/contiki,bluerover/6lbr,MohamedSeliem/contiki,arurke/contiki,arurke/contiki,arurke/contiki,MohamedSeliem/contiki,arurke/contiki,bluerover/6lbr,bluerover/6lbr,MohamedSeliem/contiki,MohamedSeliem/contiki,bluerover/6lbr,bluerover/6lbr,arurke/contiki