* added pos option to droppable event.

 * select a node when drag it.

 * make node sortable.

 * ajusted style and changed css names of mindmap.

 * added node id to the mindmap node element.

 * updated example of mindmap.

 * ajusted themes of zentao.

 * updated lightbox.

 * rebuilt zui.

 * ajusted variables setting: btn-default-bg.

 + added boards.js.

 * updated document.