[Doc] add some english documents (#220)

* [bugfix] Checkbox border render error in weixin browser

* [bugfix] TreeSelect dependency path error

* [bugfix] Swipe should clear autoplay timer when destroyed

docs/examples-docs/en-US/stepper.md

@@ -0,0 +1,68 @@
+<script>
+export default {
+  data() {
+    return {
+      stepper1: 1,
+      stepper2: null,
+    };
+  }
+};
+</script>
+
+## Stepper
+
+### Install
+``` javascript
+import { Stepper } from 'vant';
+
+Vue.component(Stepper.name, Stepper);
+```
+
+### Usage
+
+#### Basic Usage
+
+:::demo Basic Usage
+```html
+<van-stepper v-model="stepper1"></van-stepper>
+<p class="curr-stepper">当前值：{{ stepper1 }}</p>
+```
+:::
+
+#### Disabled
+通过设置`disabled`属性来禁用 stepper
+
+:::demo 禁用状态
+```html
+<van-stepper v-model="stepper1" disabled></van-stepper>
+```
+:::
+
+#### Advanced Usage
+
+默认是每次加减为1，可以对组件设置`step`、`min`、`max`、`defaultValue`属性
+
+:::demo Advanced Usage
+```html
+<van-stepper v-model="stepper2" min="5" max="40" step="2" default-value="9"></van-stepper>
+<p class="curr-stepper">当前值：{{ stepper2 || 9 }}</p>
+```
+:::
+
+### API
+
+| Attribute | Description | Type | Default | Accepted Values |
+|-----------|-----------|-----------|-------------|-------------|
+| min | 最小值 | `String | Number` | `1` | - |
+| max | 最大值 | `String | Number` | - | - |
+| defaultValue | Default | `String | Number` | `1` | - |
+| step | 步数 | `String | Number` | `1` | - |
+| disabled | 是否禁用 | `Boolean` | `false` | - | 
+| disableInput | 是否禁用input框 | `Boolean` | `false` | - |
+
+### Event
+
+| Event | Description | 回调参数 |
+|-----------|-----------|-----------|
+| change | 当绑定值变化时触发的事件 | 当前组件的值 |
+| overlimit | 点击不可用的按钮时触发 | - |