* Fix bug that could make git-annex importfeed not see recently recorded
state when configured with annex.alwayscommit=false.
* importfeed: Made "checking known urls" phase run 12 times faster.
The massive speedup is because it no longer queries for metadata
accompanying each url. Instead it processes the whole git-annex branch and
checks all metadata files for feed item ids, and uses any it finds.
This could result in a behavior change, in an unlikely situation: If a feed
id is recorded in a key's metadata, but the url gets removed, the old code
would not see that item id and would re-download it if it finds an url for
it in a feed, while the new code will see the item id. I don't think
the old behavior was intentional, and it may be that the new behavior is
better. Not gonna worry about this.
git-annex allows managing files with git, without checking the file
contents into git. While that may seem paradoxical, it is useful when
dealing with files larger than git can currently easily handle, whether due
to limitations in memory, checksumming time, or disk space.
For documentation, see doc/ or <https://git-annex.branchable.com/>