fix #64

* implement default sort

* add story for default sort

* add test for default sort

* patch docs for default sort

* a workaround to avoid render twice by story.add

packages/react-bootstrap-table2-example/examples/sort/default-sort-table.js

@@ -0,0 +1,59 @@
+/* eslint react/prefer-stateless-function: 0 */
+import React from 'react';
+
+import BootstrapTable from 'react-bootstrap-table2';
+import Code from 'components/common/code-block';
+import { productsGenerator } from 'utils/common';
+
+const products = productsGenerator();
+
+const columns = [{
+  dataField: 'id',
+  text: 'Product ID',
+  sort: true
+}, {
+  dataField: 'name',
+  text: 'Product Name',
+  sort: true
+}, {
+  dataField: 'price',
+  text: 'Product Price',
+  sort: true
+}];
+
+const defaultSorted = [{
+  dataField: 'name',
+  order: 'desc'
+}];
+
+const sourceCode = `\
+const columns = [{
+  dataField: 'id',
+  text: 'Product ID',
+  sort: true
+}, {
+  dataField: 'name',
+  text: 'Product Name',
+  sort: true
+}, {
+  dataField: 'price',
+  text: 'Product Price',
+  sort: true
+}];
+
+<BootstrapTable keyField='id' data={ products } columns={ columns } />
+`;
+
+
+class DefaultSortTable extends React.PureComponent {
+  render() {
+    return (
+      <div>
+        <BootstrapTable keyField="id" data={ products } columns={ columns } defaultSorted={ defaultSorted } />
+        <Code>{ sourceCode }</Code>
+      </div>
+    );
+  }
+}
+
+export default DefaultSortTable;