code: function index (origin) {
      var newComers = [];
      for (var _i = 1; _i < arguments.length; _i++) {
          newComers[_i - 1] = arguments[_i];
      }
      var extensions = null;
      var base = origin;
      if (isPlainObject(origin) && origin.extensions && Object.keys(origin).length === 1) {
          base = {};
          extensions = origin.extensions;
      }
      return newComers.reduce(function (result, newComer) {
          return mergeRecursively(result, newComer, extensions);
      }, base);
  }
docs: Merge anything recursively.
  Objects get merged, special objects (classes etc.) are re-assigned "as is".
  Basic types overwrite objects or other basic types.
  
  @param {(IConfig | any)} origin
  @param {...any[]} newComers
  @returns the result