Two bugfixes for layout transforms. Can now auto-add/drop a field (with default) from a record.
Added schematool_verify (stubbed).
schematool_admin: bugfixes datetime keys, schematool_backup call; rewrote migration_fun/1 and subfunctions, which now work better; added view_history/0 callback.
schematool: added history/0
schematool_backup: no longer wrap migration fun in txn, because some actions then cause nested txns.