Several bug fixes involving v6 unlocked files today. Several related bugs
were caused by relying on the inode cache information, without a fallback
to handle the case where the inode cache had not gotten updated. While the
inode cache is generally kept up-to-date well by the smudge/clean
filtering, it is just a cache and can be out of date. Did some auditing for
such problems and hopefully I've managed to find them all.

Also, there was a tricky upgrade case where a v5 repository contained a
v6 unlocked file, and the annexed content got copied into it. This
triggered the above-described bugs, and in this case the worktree needs
to be updated on upgrade, to replace the pointer file with the content.

As I caught up with recent activity, it was nice to see some contributions
from others. James MacMahon sent in a patch to improve the filenames
generated by `importfeed`. And, xloem is writing workflow documentation for
git-annex in [[todo/Workflow_guide]].
