[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

packages/checkbox/index.vue

@@ -50,7 +50,7 @@ export default {
   },
 
   computed: {
-    // checkbox 是否在 van-checkbox-group 中
+    // whether is in van-checkbox-group
     isGroup() {
       return !!this.findParentByComponentName('van-checkbox-group');
     },