【render组件】
Render继承于Component. It contians general functionality for all renderers.
A renderer is what makes an object appear on the screen. For any game object or component its renderer can be accessed trough a renderer property:
GameObject有一个renderer只读属性呆以用来访问render。
Unity4.3目前有以下8种render具体组件：
更具体信息参考：file://localhost/Applications/Unity/Unity.app/Contents/Documentation/Documentation/ScriptReference/Renderer.html
