[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/demos/views/cell.vue

@@ -0,0 +1,86 @@
+<template>
+  <demo-section>
+    <demo-block :title="$t('basicUsage')">
+      <van-cell-group>
+        <van-cell :title="$t('cell')" :value="$t('content')" />
+        <van-cell :title="$t('cell')" :value="$t('content')" :label="$t('desc')" />
+      </van-cell-group>
+    </demo-block>
+
+    <demo-block :title="$t('title2')">
+      <van-cell-group>
+        <van-cell :value="$t('content')" />
+      </van-cell-group>
+    </demo-block>
+
+    <demo-block :title="$t('title3')">
+      <van-cell-group>
+        <van-cell :title="$t('cell')" icon="location" />
+      </van-cell-group>
+    </demo-block>
+
+    <demo-block :title="$t('title4')">
+      <van-cell-group>
+        <van-cell :title="$t('cell')" is-link />
+        <van-cell :title="$t('cell')" is-link :value="$t('content')" />
+      </van-cell-group>
+    </demo-block>
+
+    <demo-block :title="$t('advancedUsage')">
+      <van-cell-group>
+        <van-cell :value="$t('content')" icon="shop" is-link>
+          <template slot="title">
+            <span class="van-cell-text">{{ $t('cell') }}</span>
+            <van-tag type="danger">{{ $t('tag') }}</van-tag>
+          </template>
+        </van-cell>
+        <van-cell :title="$t('cell')" icon="location" is-link />
+        <van-cell :title="$t('cell')">
+          <template slot="right-icon">
+            <van-icon name="search" class="van-cell__right-icon"></van-icon>
+          </template>
+        </van-cell>
+      </van-cell-group>
+    </demo-block>
+  </demo-section>  
+</template>
+
+<script>
+export default {
+  i18n: {
+    'zh-CN': {
+      cell: '单元格',
+      title2: '只设置 value',
+      title3: '展示图标',
+      title4: '展示箭头'
+    },
+    'en-US': {
+      cell: 'Cell title',
+      title2: 'Value only',
+      title3: 'Left Icon',
+      title4: 'Link'
+    }
+  },
+
+  methods: {
+    handleClick() {
+      console.log('cell click');
+    }
+  }
+};
+</script>
+
+<style lang="postcss">
+.demo-cell {
+  .van-cell-text {
+    margin-right: 5px;
+  }
+  .van-cell__right-icon {
+    font-size: 16px;
+  }
+  .van-cell-text,
+  .van-tag--danger {
+    vertical-align: middle;
+  }
+}
+</style>