will replace old dpb once we're satisfied it works.
some features:
- no more waiting, starts building right away, the dependencies discovery
process is just another job,
- monitor display that makes it easy to know when jobs get stuck, or machines
get down.
- loads of logs,
- locks that stay around in case of error, and that you can remove when
the error has been fixed (dpb picks it up),
- smart choice of which package to build,
- can take into account previous build times,
- builds on machines of differing speed, offloading "lighter" jobs to slower
boxes.
(again, ports is still locked for most people)
