Define the multiboot info struct properly so we don't have to grab at byte
offsets in the memory access checker code. Also print kernel command line
in init().
The old bootloader was hilariously complicated, requiring a floppy disk with
the kernel on it, and a hard drive with the file system. This patch removes
the floppy disk from the equation and replaces it with a multiboot header.
This means the kernel can now be booted with qemu-system-i386 -kernel kernel
