CPU Affinity code based on libnuma

@alepper, would it be possible to merge the piece of code you wrote to set the affinity into the main branch ?

It is currently part of your branch with a whole zoo of other improvements to the vectorisation. Could you provide a clean patch (branching from the current master) with the affinity setting code ?

Thanks !

I guess @pdraper can provide help with the autotools script if necessary.