v0.8.1

Fixed

• pg_improv: a measure defined after the sync worker caught up is
  computed at once. In logical mode the worker rebuilt only when a
  decoded transaction touched a bound row, and improv.define() changes
  the model, not the data, so the new result table stayed empty until the
  next write to the fact table, with no error in improv.status. The
  worker now checks model_version on every poll. logical.sh covers a
  define with no data change.