Increase the memory available for bootstrapping.
boot.S will now identity map roughly 1GB of physical memory.
If the hardware doesn't have that much available it won't be used anyway.
With this optimization in place there is no need to expand the bootstrap
VM later on. (Credit to dschatzberg on #osdev)
Remove _expand_bootstrap_vm() as it's neither needed nor called anymore.
No need to have .bootstrap inside the system VM..
Move BOOT_* tables to .bss section to the memory below 1MB clean.
Some loaders like isolinux will put the multiboot_info below 1MB.
Sinc I didn't care to check for that they would get lost..
Small refactoring.
Add packaging support (ISO only for now).