code: function relPath(s) {
    s = str(s);
    var lvls = str(s).replace(/[^/]/g, '').slice(1);
    if (lvls.length < 1 || s.slice(0,1) !== '/') return '.';
    return '..' + _.toArray(lvls).join('..').slice(0,-1);
  }
docs: return ../ for each path-level, ./ for non-absolute path or root level