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.
Fix MultipleObjectsReturned on connect_to if a host has several addresses.
Allow 3rd apps (e.g. vct) only import api.exceptions

partially reverts 01a07be8
Refactor TincHosts queryset used on connect_to
Fix problems with circular imports of permissions.

(AttributeError: NoneType has no attribute add_to_class)
Merge branch 'feature200'
Bugfix: allow cert duplicates on [Node|Server] APIs
Refactor: replace controller fixtures with datamigrations.
Bugfix #606. Keep UCI confine.server.base_path for backwards compatibility..

Required by CNS previous to c3c4e7ba567b749f9efb26a99af551fb4fc555ca
Add missing prefix length to host and gateway tinc subnet.
Remove '\r' from stored node certificates. Fixes #571.
Use PKI certificate for Server APIs on mgmt_net. refs #245

Related discussion on #571 note-9.
Fix typo: overide --> override.
Reorder postupgrade operations: take gw snapshot before drop it from database.
Fix load certificate for Server API.

Use raw SQL instead of ORM because changes on database schema are
not yet available.
Merge branch 'master' into feature603