0.4.0

Added

• clew drift: where two runs of the same workflow part ways, and why.
  Tasks paired by name, outputs compared by content digest, the cause of
  each root read from the record.
• --runs on digest, reclaim and drift: read a run straight from a
  .lineage store, a horus-lineage root, or a directory of graphs. The
  digests clew digest computes go to a sidecar under <runs>/.clew/.