This removes grub and all the loopback device business from the default
build process. Running grub takes about a second, and it turns out it's
inconsistently packaged in different distributions, which has led to
at least one confusing issue so far (grub-install vs grub2-install).
Removing it from the basic path will make it easier for people to try
Serenity out.
There are now two scripts that can be used to build a disk image:
1. `build-image-grub.sh` - this will build an image suitable for writing
to the IDE hard drive of a physical machine, complete with a partition
table and bootloader. This can be run in qemu with the `qgrub` target
for the `run` script.
2. `build-image-qemu.sh` - this is a simpler script which creates a bare
filesystem image rather than a full MBR disk.
Both of these call out to `build-root-filesystem.sh` to do most of the
work setting up... the root filesystem.
For completeness' sake, I've retained the `sync.sh` script as a simple
forwarding to `build-image-qemu.sh`.
This relies on the functionality from #194 and #195. #195 allows us to
use `/dev/hda` as the root device when nothing else is specified, and #194
works around a strange feature of qemu that appends a space to the kernel
command line.
