SMP stub

I tried to copy the MINIX 3 code for the INIT-INIT-SIPI-SIPI sequence (which
doesn't make sense to me in some parts, though) but apparently didn't
succeed in constructing working code out of it. I don't know where the error
is and it's too late to investigate.

Maybe actually initialising the LAPIC error vector makes it working (I
remember slightly to have read something pointing to this direction) or at
least it could get me a better view on the problem.

ACPI is a mess. Erm, at least my code is :-) Well, there's still time to
clean up code when we're old geezers. I only seek the quick success ;-)

I once examined the data obtained from the MADT from within qemu. Obviously,
because there is no defective hardware, it was only pairs of (CPU,LAPIC) =
xx,xx where xx ranges from 00 to 03. The relation between effort and gained
data is ridiculously distorted.

Little cleanups on other files.