0.54.3

Changed — may break callers

• documents check exits 0 when the document changed in Google since the last download. The change shows only in
  the answer: changed: true, remote_modified_at, local_modified_at, missing, next and meta.complete: false.
  Before, it exited 1, so a script took a valid answer for a failure. Real failures (not found, not signed in, network
  error) still exit non-zero.