Building GalliumOS

There are three main stages required to build images of GalliumOS.

1. deb packages: GalliumOS code needs to be pulled from github and packaged into debs. These need to be pushed to apt.galliumos.org, and also made available to the later build stages.
2. ISO images: HGB has a base files tree, onto which various upstream debs are installed, as well as GalliumOS debs. The product of this needs to be built as an ISO and pushed to our primary download site.
3. Core image files: These are very much like the ISOs, with slightly different contents and different packaging. These also need to be pushed to the download site, though they are primarily useful for commandline install (e.g. chrx).

User:reynhout is writing a build script that will handle each of these steps. I'll reuse most of HGB's existing ISO maker for that part of the process.

The script currently (20151030) builds and publishes debs (most of them -- a few are failing to build at this point, need to tweak the build environment further).

The script can be called with different args to perform different steps of the build process, so, e.g. gabuild -a make_debs will make the debs, etc. It will be easy to call from Jenkins or manually.