revise doc and set en doc's lang

Author: njleonzhang

README.md

@@ -28,6 +28,19 @@
     Vue.use(DataTables)
     ```
 
+    If you don't want import the whole `element-ui`, you can just load corresponding components refer to `On demand` section of [element-ui doc](http://element.eleme.io/#/en-US/component/quickstart)
+
+    This lib depends on the following components:
+    - el-table
+    - el-row
+    - el-col
+    - el-input
+    - el-button
+    - el-pagination
+    - el-checkbox
+    - el-checkbox-group
+
+
 2. use in your project.
 
     ```html

example/docs/en.vue

@@ -155,6 +155,10 @@
 import DataTables from '../../src/index.js'
 import {en} from '../mock'
 import CsvExport from '../utils/CsvExport'
+import lang from 'element-ui/lib/locale/lang/en'
+import locale from 'element-ui/lib/locale'
+
+locale.use(lang)
 
 export default {
   name: 'app',