A RenderOrderAction indicating to render the group with the given name.
Inheritance: AbstractRenderTraversable
        /// <summary>
        /// Handle a RenderGroup action in the RenderOrder.
        /// </summary>
        /// <param name="action"></param>
        private void HandleRenderOrderAction_RenderGroup(
            RenderOrder.RenderGroup action, RenderableHandler renderAction)
        {
            var group = AllRenderables.GetSubnode(action.Name);

            group.Render(action.Options, renderAction, SeenRenderables, SeenGroups, action.SkipDuplicates);
        }