[new feature] add i18n support (#310)

* fix: Tabbar icon line-height

* [new feature] progress add showPivot prop

* [new feature] TabItem support vue-router

* [new feature] update document header style

* [Doc] add toast english ducoment

* [new feature] add i18n support

* feat: Extract demos from markdown

* feat: Base components demos

* [new feature] complete demo extract & translate

* [fix] text cases

* fix: add deepAssign test cases

* fix: changelog detail

* [new feature] AddressEdit support i18n

docs/markdown/zh-CN/badge.md

@@ -0,0 +1,51 @@
+## Badge 徽章
+
+### 使用指南
+``` javascript
+import { Badge } from 'vant';
+
+Vue.component(Badge.name, Badge);
+```
+
+### 代码演示
+
+#### 基础用法
+
+通过在`van-badge-group`上设置`active-key`属性来控制选中的`badge`
+
+```html
+<van-badge-group :active-key="activeKey">
+  <van-badge title="热销榜" @click="onClick"></van-badge>
+  <van-badge title="花式寿司" @click="onClick" info="8"></van-badge>
+  <van-badge title="火炽寿司" @click="onClick" info="99"></van-badge>
+  <van-badge title="手握寿司" @click="onClick" info="199"></van-badge>
+</van-badge-group>
+```
+
+``` javascript
+export default {
+  data() {
+    return {
+      activeKey: 0
+    };
+  },
+  methods: {
+    onClick(key) {
+      this.activeKey = key;
+    }
+  }
+};
+```
+
+### BadgeGroup API
+
+| 参数 | 说明 | 类型 | 默认值 | 可选值 |
+|-----------|-----------|-----------|-------------|-------------|
+| active-key | 选中`badge`的索引 | `String | Number` | `0` | - |
+
+### Badge API
+| 参数 | 说明 | 类型 | 默认值 | 可选值 |
+|-----------|-----------|-----------|-------------|-------------|
+| title | 内容 | `String` | `''` | - |
+| info | 提示消息 | `String` | `''` | - |
+| url | 跳转链接 | `String` | - | - |