Conflicts, rebase and cherry-pick

Ropenode has a proper merge-conflict resolver: for each conflicting file, take ours, take theirs, or edit the merged result by hand, then mark it resolved.

Rebase onto… and cherry-pick (from the history view) both route their conflicts into the same resolver, and a persistent banner tells you what operation is in progress with Continue and Abort always available — so you can never get stranded mid-rebase wondering what state the repo is in.