Not a lot of coding the past few days, but a lot of skull sweat!

I've been working through the design for the [[todo/import_tree]] feature,
and I think I finally have a design that I'm happy with. There were some
very challenging race conditions, and so import tree may only be safely
able to be implemented for a few remotes; S3 (with versioning enabled),
directory, maybe webdav and I hope adb. Work on this included finding
equivilant race conditions in git's update of the worktree, which do
turn out to exist if you go looking, but have much narrower time
windows there.

And I'll be running a tutorial for people who want to
learn about git-annex internals at the code level, to start development or
be better able to design their own features. That's in Montreal, March
26th-27th (8 hours total), hosted at McGill university. There may be one or
two seats left, so if you are interested in attending, please get in touch
with me by email. Haskell is not a prerequisite.
