[new feature] ImagePreview support manually close (#346)

* 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

* [bugfix] Search box-sizing wrong

* [Doc] update vant-demo respo

* [Doc] translate theme & demo pages

* [Doc] add Internationalization document

* [bugfix] remove unnecessary props

* [fix] optimize clickoutside

* [new feature] optimize find-parent

* [new feature]: change document title accordinng to language

* [new feature] Pagination code review

* [improvement] adjust icon-font unicode

* [improvement] Icon spinner color inherit

* [improvement] icon default width

* [bugfix] DateTimePicker validate date props

* [bugfix] Tab item text ellipsis

* [improvement] optimize single line ellipsis

* [Improvement] optimzie staticClass

* [Improvement] Button: use sfc instread of jsx

* [Improvement] update actionsheet close icon style

* fix: yarn.lock

* fix: icon test cases

* [bugfix] errors during ssr

* [Improvement] SubmitBar add left slot

* [new feature] ImagePreview support manually close

* fix: ImagePreview test case

docs/demos/views/image-preview.vue

@@ -7,6 +7,10 @@
     <demo-block :title="$t('button2')">
       <van-button @click="showImagePreview(1)">{{ $t('button2') }}</van-button>
     </demo-block>
+
+    <demo-block :title="$t('button3')">
+      <van-button @click="showImagePreview(0, 1000)">{{ $t('button3') }}</van-button>
+    </demo-block>
   </demo-section>
 </template>
 
@@ -17,21 +21,29 @@ export default {
   i18n: {
     'zh-CN': {
       button1: '预览图片',
-      button2: '指定初始位置'
+      button2: '指定初始位置',
+      button3: '手动关闭'
     },
     'en-US': {
       button1: 'Show Images',
-      button2: 'Custom Start Position'
+      button2: 'Custom Start Position',
+      button3: 'Close Manually'
     }
   },
 
   methods: {
-    showImagePreview(position) {
-      ImagePreview([
+    showImagePreview(position, timer) {
+      const instance = ImagePreview([
         'https://img.yzcdn.cn/upload_files/2017/03/15/FkubrzN7AgGwLlTeb1E89-T_ZjBg.png',
         'https://img.yzcdn.cn/upload_files/2017/03/14/FmTPs0SeyQaAOSK1rRe1sL8RcwSY.jpeg',
         'https://img.yzcdn.cn/upload_files/2017/03/15/FvexrWlG_WxtCE9Omo5l27n_mAG_.jpeg'
       ], typeof position === 'number' ? position : 0);
+
+      if (timer) {
+        setTimeout(() => {
+          instance.close();
+        }, timer);
+      }
     }
   }
 };