fix#264: wrong col span when enable selection in a empty table (#265)

* noDataIndication

* use the correct amount of cells when the first row is select
* storybook added for development, not necessary in docs

fixes react-bootstrap-table/react-bootstrap-table2#264

* eslint complaints

  4:11  error  'columnLen' is never reassigned. Use 'const' instead                   prefer-const
  7:9   error  Expected an assignment or function call and instead saw an expression  no-unused-expressions

* tests updated

packages/react-bootstrap-table2-example/examples/row-selection/selection-no-data.js

@@ -0,0 +1,62 @@
+/* eslint no-unused-vars: 0 */
+import React from 'react';
+
+import BootstrapTable from 'react-bootstrap-table-next';
+import Code from 'components/common/code-block';
+
+const columns = [{
+  dataField: 'id',
+  text: 'Product ID'
+}, {
+  dataField: 'name',
+  text: 'Product Name'
+}, {
+  dataField: 'price',
+  text: 'Product Price'
+}];
+
+const selectRow1 = {
+  mode: 'checkbox',
+  clickToSelect: true
+};
+
+const sourceCode1 = `\
+import BootstrapTable from 'react-bootstrap-table-next';
+
+const columns = [{
+  dataField: 'id',
+  text: 'Product ID'
+}, {
+  dataField: 'name',
+  text: 'Product Name'
+}, {
+  dataField: 'price',
+  text: 'Product Price'
+}];
+
+const selectRow = {
+  mode: 'checkbox',
+  clickToSelect: true
+};
+
+<BootstrapTable
+  keyField='id'
+  data={ [] }
+  columns={ columns }
+  selectRow={ selectRow }
+  noDataIndication={ 'no results found' }
+/>
+`;
+
+export default () => (
+  <div>
+    <BootstrapTable
+      keyField="id"
+      data={ [] }
+      columns={ columns }
+      selectRow={ selectRow1 }
+      noDataIndication={ 'no results found' }
+    />
+    <Code>{ sourceCode1 }</Code>
+  </div>
+);