code: function map(tree, method, args) {
      return tree.model[method].apply(tree.model, args);
  }
docs: Maps a method to the root TreeNodes collection.
  
  @private
  @param {InspireTree} tree Tree instance.
  @param {string} method Method name.
  @param {arguments} args Proxied arguments.
  @return {mixed} Proxied return value.