the modloop will need loop and cramfs modules. Those are only available
in initramfs stage so we must make sure they are properly loaded.

otherwise will awk not detect empty fields

saves us for lots of headache.

seems like copy removes destination if source does not exist so
we ended up with a buildrepo that removed all packages

abuild will not consider package up2date unless apk cache is up2date

with support for dynamic dependencies

use USBIMG_FREE to set how many kB you want to have as free space on
usb image.

The sda1 might be a sata or scsi harddisk so usb image might be sdb1 or sdc1.
The /dev/usbdisk link will always point to the first usb disk.

The APK_FILES does not contain the dependencies for the wanted packages
so we cannot use this variable when generating the index.

Basicly, let apk-tools deal with the dependencies rather than let abuild do it

This is so you can build the iso image without having the aports tree.

fixes #28

The tmprepo is a temporary repository used by abuild to handle the
dependencies of the newly built packages.