code: function _aliasRead(item, callback, err, orig) {
    if (err) return callback(err);
    item.orig = orig;
    callback(null, item);
  }
docs: Updates the item with path to its original file.
  @param {Object} item - Object representing investigated symbolic link.
  @param {Function} callback - Callback that expects a possible error
  and the item.
  @param {*} err - Possible error passed by caller.
  @param {String} orig - Content of the symbolic link.