Feature request: Implement AS lookup

[mabra]

In a moving world, hostnames are nothing, which persist too long ;) At least, if one verifies the path of (own) nodes, the usual 'traceroute' has the nice option '-A', which shows the AS numbers, a host resides in. This, in opposite to a found host, does not change fast and can be really used to verify a path, which may be a security aspect.