[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/steps.vue

@@ -0,0 +1,113 @@
+<template>
+  <demo-section>
+    <demo-block :title="$t('basicUsage')">
+      <van-steps :active="active">
+        <van-step>{{ $t('step1') }}</van-step>
+        <van-step>{{ $t('step2') }}</van-step>
+        <van-step>{{ $t('step3') }}</van-step>
+        <van-step>{{ $t('step4') }}</van-step>
+      </van-steps>
+
+      <van-button @click="nextStep">{{ $t('nextStep') }}</van-button>
+    </demo-block> 
+
+    <demo-block :title="$t('title2')">
+      <van-steps
+        :active="active"
+        icon="logistics"
+        icon-class="steps-success"
+        :title="$t('title')"
+        :description="$t('desc')"
+      >
+        <van-step>{{ $t('step1') }}</van-step>
+        <van-step>{{ $t('step2') }}</van-step>
+        <van-step>{{ $t('step3') }}</van-step>
+        <van-step>{{ $t('step4') }}</van-step>
+      </van-steps>
+    </demo-block>
+
+    <demo-block :title="$t('title3')">
+      <van-steps direction="vertical" :active="0" active-color="#f60">
+      <van-step>
+        <h3>{{ $t('status1') }}</h3>
+        <p>2016-07-12 12:40</p>
+      </van-step>
+      <van-step>
+        <h3>{{ $t('status2') }}</h3>
+        <p>2016-07-11 10:00</p>
+      </van-step>
+      <van-step>
+        <h3>{{ $t('status3') }}</h3>
+        <p>2016-07-10 09:30</p>
+      </van-step>
+    </van-steps>
+    </demo-block>
+  </demo-section>
+</template>
+
+<script>
+export default {
+  i18n: {
+    'zh-CN': {
+      nextStep: '下一步',
+      step1: '买家下单',
+      step2: '商家接单',
+      step3: '买家提货',
+      step4: '交易完成',
+      title2: '物流描述',
+      title3: '竖向步骤条',
+      status1: '【城市】物流状态1',
+      status2: '【城市】物流状态',
+      status3: '快件已发货'
+    },
+    'en-US': {
+      nextStep: 'Next Step',
+      step1: 'Step1',
+      step2: 'Step2',
+      step3: 'Step3',
+      step4: 'Step4',
+      title2: 'Description',
+      title3: 'Vertical Steps',
+      status1: '【City】Status1',
+      status2: '【City】Status2',
+      status3: '【City】Status3'
+    }
+  },
+
+  data() {
+    return {
+      active: 0
+    };
+  },
+
+  methods: {
+    nextStep() {
+      this.active = ++this.active % 4;
+    }
+  }
+}
+</script>
+
+<style lang="postcss">
+.demo-steps {
+  .steps-success,
+  .van-icon-location {
+    color: #06bf04;
+  }
+
+  .van-button {
+    margin: 15px 0 0 15px;
+  }
+
+  .van-steps__message + p {
+    margin-bottom: 10px;
+  }
+
+  p,
+  h3 {
+    margin: 0;
+    font-size: inherit;
+    font-weight: normal;
+  }
+}
+</style>