[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/en-US/cell-swipe.md

@@ -0,0 +1,37 @@
+## CellSwipe
+
+### Install
+``` javascript
+import { CellSwipe } from 'vant';
+
+Vue.component(CellSwipe.name, CellSwipe);
+```
+
+### Usage
+
+#### Basic Usage
+
+```html
+<van-cell-swipe :right-width="65" :left-width="65">
+  <span slot="left">Select</span>
+  <van-cell-group>
+    <van-cell title="Cell" value="Cell Content"></van-cell>
+  </van-cell-group>
+  <span slot="right">Delete</span>
+</van-cell-swipe>
+```
+
+### API
+
+| Attribute | Description | Type | Default | Accepted Values |
+|-----------|-----------|-----------|-------------|-------------|
+| left-width | Width of the left scrollable area | `Number` | `0` | - |
+| right-width | Width of the right scrollable area | `Number` | `0` | - |
+
+### Slot
+
+| name | Description |
+|-----------|-----------|
+| - | custom content |
+| left | content of left scrollable area |
+| right | content of right scrollabe area |