loopback addresses

[rwestphal]

In the topology file, it's possible to configure IP addresses for all connections (veth interfaces). However, I couldn't find an option to configure IP addresses for the loopback interfaces. Am I missing something?

It'd be particularly awesome if networks-autonumber could also work for loopback addresses (e.g. starting from 10.0.255.1/32). That would reduce the amount of manual configs I need to add in my test topologies.