Added migrations for contacts and started working through thread migration (have contact and closed group threads migrating)
Deprecated usage of ECKeyPair in the migrations (want to be able to remove Curve25519Kit in the future)
Updated the migrations so they can specify whether a configuration sync is required
Moved the config sync logic into a MessageSender extension (makes far more sense than AppDelegate)
Fixed a bug where the ShareVC was triggering the 'versionMigrationsDidComplete' twice
Removed a couple of imports for files that had been deleted
Fixed an issue where sharing form Safari without adding comments would result in an invalid message getting sent.
Fixed a crash when sharing plain text from safari.
Fixed a crash when localising 'OK' (key and value can't be the same when using the new extension).