Migrate data: sliver_data XOR sliver_overlay (#200)
Remove overlay fields of sliver (#200).
Merge branch 'master' into feature200

Apply feature236 changes into feature200.
Fix typo in warning about overlay settings removed.
Merge branch 'feature200'
Bugfix: allow cert duplicates on [Node|Server] APIs
Refactor: replace controller fixtures with datamigrations.
Merge branch 'master' into bug585