Got a bit distracted improving Haskell's directory listing code.

Only real git-annex work today was fixing [[bugs/Assistant_merge_loop]],
which was caused by changes in the last release (that made direct mode
merging crash/interrupt-safe). This is a kind of ugly bug, that can result
in the assistant making lots of empty commits in direct mode repositories.
So, I plan to make a new release on Monday.
