[Merge] livecd-rootfs:ui-by-default into livecd-rootfs:ubuntu/master

[Łukasz Zemczak]

The aforementioned cdimage changes will come later, as this depends on what kind of naming scheme we decide on for artifacts in our official image-definitions.
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https://code.launchpad.net/~ubuntu-core-dev/livecd-rootfs/+git/livecd-rootfs/+merge/434682
Your team Ubuntu Core Development Team is requested to review the proposed merge of livecd-rootfs:ui-by-default into livecd-rootfs:ubuntu/master.