Got well caught up on bug fixes and traffic. Backlog is down to 40.

Made the assistant wait for a few seconds before doing the startup
scan when it's autostarted, since the desktop is often busy starting
up at that same time.

Fixed an ugly bug with chunked webdav and directory special remotes
that caused it to not write a "chunkcount" file when storing data,
so it didn't think the data was present later. I was able to make it
recover nicely from that mistake, by probing for what chunks are actually
present.

Several people turn out to have had problems with `git annex sync` not
working because receive.denyNonFastForwards is enabled. I made the webapp
not enable it when setting up a ssh repository, and I made `git annex sync`
print out a hint about this when it's failed to push. (I don't think this
problem affects the assistant's own syncing.)

Made the assistant try to repair a damaged git repository without
prompting. It will only prompt when it fails to fetch all the lost
objects from remotes.

Glad to see that others have managed to 
[get git-annex to build on Max OS X 10.9](http://git-annex.branchable.com/bugs/git_annex_doesn__39__t_work_in_Max_OS_X_10.9/#comment-8e8ee5e50506a6fde029d236f4809df8). 
Now I just need someone to offer up a ssh account on that OS, and I could
set up an autobuilder for it.
