Use machine wrap around in allocation

[rowleya]

If the machine wrap arounds can be used during allocation, a large machine could be allocated that makes use of this. In turn, this would allow the allocations of boards to be rotated, since as allocations moved towards the nominal centre of the machine, larger jobs could be allocated taking advantage of the wrap around.

[alan-stokes]

didn't we discuss this at one point, and the issue is that the boards that are wired to be the next board in the 1 million machine are not on the same racks/cabinates etc, and therefore the bmp programming was a issue.

i vaguely renember @lplana saying that making sub wraps was much more complicated than big machine and 2d fabrics.