Get rid of permutation table in dynamic Maglev

[eoglaba]

Fixes #18

This change gets rid of the huge permutation table. It turns out that the necessary values can be computed just as fast on the fly: there's no need to retrieve them from memory.
Another modification is that nfqlb (de)activate computes the new lookup table in a temporary array and copies the results to the actual lookup table in shared memory only when the Maglev computation is done: this makes sure that the loadbalancer does not throw away packets while Maglev computation is taking place.

This PR changes only the dynamic Maglev computation: the static Maglev parts (which are used only for reference) still use the old permutation table-based method.

Attached is a graph about the overall speedup achieved in the populate function. The proposed new method creates an equivalent lookup table.

As you see, the new method is faster until we have about 60 targets or so.