Add confirmLoading prop for Modal

You can use `confirmLoading` to cancel button loading status.

```
onOk() {
  ...
  this.setState({
    confirmLoading: false
  });
}
```

Fix #322

components/modal/demo/basic.md

@@ -23,6 +23,7 @@ var Test = React.createClass({
   handleOk() {
     console.log('点击了确定');
     this.setState({
+      confirmLoading: false,
       visible: false
     });
   },
@@ -36,6 +37,7 @@ var Test = React.createClass({
       <button className="ant-btn ant-btn-primary" onClick={this.showModal}>显示对话框</button>
       <Modal title="第一个 Modal"
         visible={this.state.visible}
+        confirmLoading={this.state.confirmLoading}
         onOk={this.handleOk}
         onCancel={this.handleCancel}>
         <p>对话框的内容</p>

components/modal/index.jsx

@@ -40,16 +40,18 @@ let AntModal = React.createClass({
   },
 
   componentWillReceiveProps(nextProps) {
+    let newState = {};
     if ('visible' in nextProps) {
-      let newState = {
-        visible: nextProps.visible
-      };
-      // 隐藏后去除按钮 loading 效果
+      newState.visible = nextProps.visible;
+      // 隐藏后默认去除按钮 loading 效果
       if (!nextProps.visible) {
         newState.confirmLoading = false;
       }
-      this.setState(newState);
     }
+    if ('confirmLoading' in nextProps) {
+      newState.confirmLoading = nextProps.confirmLoading;
+    }
+    this.setState(newState);
   },
 
   componentDidMount() {

components/modal/index.md

@@ -20,9 +20,10 @@
 
 | 参数       | 说明           | 类型             | 默认值       |
 |------------|----------------|------------------|--------------|
+| visible    | 对话框是否可见 | Boolean          | 无           |
+| confirmLoading | 确定按钮 loading | Boolean    | 无           |
 | title      | 标题           | React.Element    | 无           |
-| mousePosition      | 鼠标位置，设置弹窗初始位置           | {x:number,y:number}   | 无           |
-| onOk       | 点击确定回调       | function         | 无           |
+| onOk       | 点击确定回调       | function     | 无           |
 | onCancel   | 点击遮罩层或右上角叉或取消按钮的回调  | function  | 无           |
 | width      | 宽度           | String or Number | 520           |
 | footer     | 底部内容       | React.Element    | 确定取消按钮 |

style/components/button.less

@@ -42,20 +42,26 @@
     .btn-circle-outline;
   }
 
+  &:after {
+    font-family: anticon;
+    content: "\e610";
+    position: absolute;
+    opacity: 0;
+    transition: opacity 0.5s ease;
+  }
+
   &-loading {
     padding-right: 31px;
     pointer-events: none;
     opacity: 0.75;
     &:after {
-      font-family: anticon;
       .animation(loadingCircle 1s infinite linear);
-      content: "\e610";
-      position: absolute;
       height: 12px;
       line-height: 12px;
-      right: 13px;
+      right: 12px;
       top: 50%;
       margin-top: -6px;
+      opacity: 1;
     }
   }