code: function normalizeId(idFromRoot, root) {
    var id = idFromRoot.substring().trim();
    if (root && id.length > 0 && id[0] === '/') {
      id = id.substring(1);
    }
    id = root + id;
    return id;
  }
docs: Return a module id which can be used by the builtin `require()`.
  @param {String} idFromRoot A RFR module id.
  @param {String} root The root.
  @returns {String} A standard module id.
  @private