Mir in Ubuntu

[Christopher James Halse Rogers]

It looks like it's about time to land some of Mir¹ in Ubuntu.

Since the system compositor depends on the Mir server API, which we've 
made no effort to make ABI-stable, I don't think we can reasonably 
autoland mir+unity-system-compositor into the distro.

This probably means that we should do some form of periodic releases, 
which go in the distro. I think something like a weekly or fortnightly 
release would be appropriate.

This also raises the question of how much support, in the form of 
post-release stable updates, we'll give the Mir in desktop 13.10 - my 
current understanding is “basically none”, but we'll need to think 
about branching a stable branch etc if that's incorrect.

¹: https://blueprints.launchpad.net/ubuntu/+spec/client-1303-mir-xorg