update examples

README-zh_CN.md

@@ -19,11 +19,21 @@
 
 ## 示例
 
+### 使用全部组件
+
 ```jsx
 import { Datepicker } from 'antd';
 ReactDOM.render(<Datepicker />, mountNode);
 ```
 
+### 按需使用
+
+```jsx
+import "antd/lib/index.css"; // 只需在页面入口模块引用一次
+import Datepicker from 'antd/lib/datepicker';
+ReactDOM.render(<Datepicker />, mountNode);
+```
+
 ## 链接
 
 - [首页](http://ant.design/)

README.md

@@ -15,11 +15,21 @@ An enterprise-class UI design language and React-based implementation.
 
 ## Usage example
 
+### Use all components
+
 ```jsx
 import { Datepicker } from 'antd';
 ReactDOM.render(<Datepicker />, mountNode);
 ```
 
+### Use on demand
+
+```jsx
+import "antd/lib/index.css"; // only need to import once in entry module
+import Datepicker from 'antd/lib/datepicker';
+ReactDOM.render(<Datepicker />, mountNode);
+```
+
 ## Links
 
 - [Home page](http://ant.design/)