Feature/english (#381)

* perf[navbar]: set langSelect to component && refine errorLog component

* feat[login]:add 18n to login form

* fix[pagination]: fixed when selected page-sizes

* perf[i18n]:dashboard document svg permission

* perf[charts]: perf effect

* perf[i18n]:excel && zip

* perf[i18n]: table && errorLog && theme

* perf[i18n]: components

* perf[i18n]: direct use $t

* perf[i18n]: complex-table

* update README.md

* update README.md 📘

* perf[i18n]: refine code comments

src/views/components-demo/markdown.vue

@@ -1,14 +1,14 @@
 <template>
   <div class="components-container">
-    <code>Markdown 我们这里选用了
-      <a href="https://github.com/sparksuite/simplemde-markdown-editor" target="_blank">simplemde-markdown-editor</a> ，简单的用vue封装了一下
+    <code>Markdown is based on
+      <a href="https://github.com/sparksuite/simplemde-markdown-editor" target="_blank">simplemde-markdown-editor</a> ，Simply encapsulated in Vue.
       <a target="_blank" href="https://segmentfault.com/a/1190000009762198#articleHeader14">
         相关文章 </a>
     </code>
     <div class="editor-container">
       <markdown-editor id="contentEditor" ref="contentEditor" v-model="content" :height="300" :zIndex="20"></markdown-editor>
     </div>
-    <el-button @click="markdown2Html" style="margin-top:80px;" type="primary" icon="el-icon-document">转为HTML</el-button>
+    <el-button @click="markdown2Html" style="margin-top:80px;" type="primary" icon="el-icon-document">To HTML</el-button>
     <div v-html="html"></div>
   </div>
 </template>