Monthly hacks: vc-arch.el

I will finish at least one major hack per month. This month’s special
is vc-arch.el, which for some reason does not seem available on the
Net. I have sketches of it up at ../emacs/emacs-wiki/vc-arch.el. I
feel that if nothing else, at least I’ll have a mode that makes it
easier for me to manage my planner work.

Getting a diff through C-x v = already works. I want to be able to
commit my changes with a quick C-x v v. If more than one file has been
modified, I want a dired-like buffer displayed so that I can select
which files to commit.