Changes to get it running

I needed to do some changes in the build process in order to run the VM.

1. I was not able to run the image with VirtualBox 4.1.2 and I was not able to install VB 4.3 on Ubuntu 12.04.
2. I gave qemu a try and I found out that I need to download a special bios for it.
3. I added some dependencies into the Makefile, so now one should be able to download `qemu-bios/bios.bin` and `make qemu` from a clean repo to get running.
4. With the original uefi_bootloader.c, I got the error "CR has Bad Signature."