Do not require unreal mode, load stage 2 in conventional memory

asm/x86-unknown-none/bootloader.asm

asm/x86-unknown-none/cpuid.asm

asm/x86-unknown-none/memory_map.asm

asm/x86-unknown-none/stage1.asm

asm/x86-unknown-none/stage2.asm

asm/x86-unknown-none/unreal.asm

linkers/x86-unknown-none.ld

src/lib.rs

src/logger.rs

src/macros.rs

src/memory_map.rs

src/panic.rs

src/vga.rs