code: function name(fp, options) {
    var opts = options || {};
    if (typeof opts.namespace === 'function') {
      return opts.namespace(fp, opts);
    }
    if (typeof opts.namespace === false) {
      return fp;
    }
    var ext = path.extname(fp);
    return path.basename(fp, ext);
  }
docs: Default `namespace` function. Pass a function on `options.namespace`
  to customize.
  
  @param {String} `fp`
  @param {Object} `opts`
  @return {String}
  @api private