Lots of little fixes and improvements here and there over the past couple
days.

The main thing was fixing several bugs with adjusted branches and Windows.
They seem to work now, and commits made on the adjusted branch are
propigated back to master correctly.

It would be good to finish up the last todos for v6 mode this month.
The sticking point is I need a way to update the file stat in the git index
when git-annex gets/drops/etc an unlocked file. I have not decided yet if
it makes the most sense to add a dependency on libgit2 for that, or extend
`git update-index`, or even write a pure haskell library to manipulate
index files. Each has its pluses and its minuses.
