Replace RoutingTableEntry with a tuple
Currently, the RoutingTable stores entries as a class, RoutingTableEntry. All this does is provide getters and setters, and define equality. A tuple provides equality comparison by element-wise comparison, which is exactly how RoutingTableEntry currently implements it.
Separating this data container into a class suggests that it has some kind of behavior or state modification. However, it is only a data container, so a POD is more appropriate. A tuple is better than a struct in this situation because C++11 provides a built-in operator== for tuples, but not structs.