Lindent on the new APIC/ACPI files

And the MP tables!  Oh, and devarch.
Extracts sigscan/checksum

Helpers to scan memory for a signature/pattern.  Now we can use them in
multiple places, without have the same code twice.
ACPI init reorg

Init the ACPI as soon as possible, and handle the APIC during IDT init.
Various APIC debugging and IOAPIC IRQ routing

Still busted, but getting a bit closer.  apiconline() needs work, and needs to
be called for all cores.  IOAPIC routing is broken, and the interfaces to IRQ
code are sloppy.  We have a weird mix of plan9 code and Akaros code that do
different things with PCI and IRQ handling.