TODO

- Ensure no space between filename and number.

Do not want:

  $ git number --column
  On branch master
  Your branch is up-to-date with 'github/master'.

  Untracked files:
    (use "git add <file>..." to include in what will be committed)

  1       b2  c

  nothing added to commit but untracked files present (use "git add" to track)

Should be:

  $ git number --column
  On branch master
  Your branch is up-to-date with 'github/master'.

  Untracked files:
    (use "git add <file>..." to include in what will be committed)

  1       b 2 c

  nothing added to commit but untracked files present (use "git add" to track)

- Ignored files shown by "git status --ignored" is not shown by "git number -- ignored"