Introduce StatusOptions.IncludeUnaltered

Test can be improved, what else needs done?
>That includes the .git directory for some reason.

Huh? That's weird. Outputting to Console the content of Unaltered on my box renders the following

```
Unaltered: 1.txt
Unaltered: 1\branch_file.txt
Unaltered: branch_file.txt
Unaltered: branch_file.txt
Removed: deleted_staged_file.txt
Missing: deleted_unstaged_file.txt
Unaltered: deleted_unstaged_file.txt
Unaltered: modified_staged_file.txt
Staged: modified_staged_file.txt
Modified: modified_unstaged_file.txt
Unaltered: modified_unstaged_file.txt
Unaltered: new.txt
Unaltered: new.txt
Unaltered: new_tracked_file.txt
Added: new_tracked_file.txt
Untracked: new_untracked_file.txt
Unaltered: README
```