carbs rootfs script

Tool for generating rootfs tarballs for Carbs Linux. This tool now uses cpt for
building the tarball. The old version of the tool which used kiss can be found
on the seperate branch 'kiss'.


Configuration can be done by copying config.def file to config. There you can
configure where the rootfs will be created, packages to be installed, CFLAGS,
MAKEFLAGS, repository to be added, and the `CPT_PATH` to be used.

extra repositories

The script by default only installs a single repository, but can accept a file
named 'repositories' to add additional repositories to the target system. This
file is structured in a plaintext manner and has 3 seperate sections.

1. Git URL
2. Target location
3. Git clone options (such as --depth 1)

Here is an example repositories file. The local repository is for example
purposes, don't actually use local repositories.

  | https://git.u.com/repo1 /var/db/cpt/personalrepo --depth 1               |
  | /home/user/cpt-repo2   /var/db/cpt/cpt-repo2   --no-local --depth 2      |

You can then add these to your CPT_PATH by editing the config file and adding
the following to your `HOST_REPO_PATH`.



You can change the postinstall (which defaults to true) function to make manual
changes to the generated root filesystem.