[Cake] Per-host fairness

[Georgios Amanakis]

I tried with "besteffort dual-dsthost nat" on ifb ingress and
"besteffort dual-srchost nat" on WAN egress, and when doing simple
things (i.e. downloading from a couple of websites) the bandwidth is
divided fair per-host, i.e 1:1 between A and B. However, when one of
the hosts is using bittorrent, he also gets most of the bandwidth, i.e.
if total ingress bandwidth is 3300kbit, A is using bittorrent and gets
2900kbit, B is downloading from a single website and gets 400kbit.