Merge branch 'jk/diff'

Merge branch 'jk/diff'

* jk/diff:
  wt-status: remove extraneous newline from 'deleted:' output
  git-status: document colorization config options
  Teach runstatus about --untracked
  git-commit.sh: convert run_status to a C builtin
  Move color option parsing out of diff.c and into color.[ch]
  diff: support custom callbacks for output