Ubuntu daily quality improvements; overlap with Debian CUT

In Ubuntu, we have been making a number of systematic improvements to the stability of our development release, aiming to have it be usable every day by reasonably technical people who are not working on the distribution itself, and to ensure that we can produce functional installation images every day. This has been done by a combination of throwing manpower at the problem (e.g. the "+1 maintenance team") and technology (e.g. interposing a version of britney with somewhat modified policies, and a variety of Jenkins tests). We will present our current state by comparison with a year ago, and look forward to discussing the overlap of this work with Debian's CUT (Constantly Usable Testing) project.