v2.5.1

Changed

• end_session waits up to 58 s, as checkpoint does: from ShadowGit 0.3.13 the app takes the session's unsaved
  edits into a snapshot before it answers. When it has, the answer names that snapshot, and its next step goes
  straight to get_lens. An older app answers as before.
• checkpoint lists the rules check of a checkpoint that finds nothing new. Outside a session the app's automatic
  snapshot can take the change first; from ShadowGit 0.3.13 the app checks that snapshot.