• Expander icon disappeared while lazy loading (issue 167).
• Allow empty lists when loading lazily (issue 168).
• New callback tree.onRender(node, span) allows changing or binding after HTML markup was created.
• New callback tree.onCustomRender(node) allows passing custom HTML markup for node titles.
• New method tree.renderInvisibleNodes() forces creation of all HTML elements.
  node.render() has new argument includeInvisible.
• New methods tree.count() and node.countChildren().
• Updated to jQuery 1.4.4 / jQuery-UI 1.8.7