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/example/table/dynamicTable/unfixedThead.vue

@@ -12,7 +12,7 @@
     <el-table :data="tableData" border fit highlight-current-row style="width: 100%">
       <el-table-column prop="name" label="fruitName" width="180">
       </el-table-column>
-      <el-table-column :key='fruit' v-for='(fruit,index) in formThead' :label="fruit">
+      <el-table-column :key='fruit' v-for='fruit in formThead' :label="fruit">
         <template slot-scope="scope">
           {{scope.row[fruit]}}
         </template>