Directory mode for use with git difftool

[brianj29]

Thanks much for continuing the development of diffuse! It has been my favorite graphical diff tool for many years.

I'd like to request a directory diff mode, where I can give diffuse two directories, and it determines which files have changed between them, and diffs the files individually in separate panes. It would be handy to have for an additional UI (eg. an extra tab, or side panel) showing which paths have changes. The goal is to integrate with "git difftool -d", but it would be useful in other situations as well.

Feature request #190 would provide similar functionality for me at the end of the day, but a generalized directory-diff would be more universal.

As an example, meld does a good job with this.