AggregateInterface can be used to gather multiple libpcap interfaces
together in order to listen to all simultaneously and also selectively
send on different interfaces
this just involved a better understanding of the data
types provided by libnl and some refactoring to make querying
as a user of the libnl library easier
there was an attempt to use libnl to look up addresses directly with
FIB_LOOKUP, and some of that code was left over. This commit cleans up
such leftover code
