Finally got the remote tracking branch for import from S3 into a good shape.

Rather than coaxing git into generating the same commits each time for imports (which would have needed commit dates to be stable somehow), I made git-annex always preserve a reference to the last import commit.

Here's how it looks when a rename was exported to S3, which resulted in a history in S3 that diverged and reconverged with the git history.

And here's how the history develops as more changes get exported and imported.

With adb and S3 import done, the first phase of ?import tree is complete.