Fwd: [PATCH v2 02/18] Add a new builtin: branch-diff

[Øyvind Rønningstad]

Just want to throw my support in for range-diff since ranges is what
you pass to the command.

Alternatively, diff-diff since that's how I've crudely tried to
accomplish this before.

git diff A..B > diff1
git diff C..D > diff2
winmerge diff1 diff2