Feature/Allow to display search bar from init (gregnb#893)

* Add option to display search bar at init

* rename showSearch to searchOpen. add propType.

* Revert "rename showSearch to searchOpen. add propType."

* fixed: searchOpen with propType

README.md

@@ -167,6 +167,7 @@ The component accepts the following props:
 |**`sort`**|boolean|true|Enable/disable sort on all columns
 |**`filter`**|boolean|true|Show/hide filter icon from toolbar
 |**`search`**|boolean|true|Show/hide search icon from toolbar
+|**`searchOpen`**|boolean|false|Initially displays search bar  
 |**`searchText`**|string||Initial search text
 |**`searchPlaceholder`**|string||Search text placeholder. [Example](https://github.com/gregnb/mui-datatables/blob/master/examples/customize-search/index.js)
 |**`print`**|boolean|true|Show/hide print	 icon from toolbar

src/MUIDataTable.js

@@ -168,6 +168,7 @@ class MUIDataTable extends React.Component {
       customSort: PropTypes.func,
       customSearch: PropTypes.func,
       search: PropTypes.bool,
+      searchOpen: PropTypes.bool,
       searchText: PropTypes.string,
       searchPlaceholder: PropTypes.string,
       print: PropTypes.bool,

src/components/TableToolbar.js

@@ -80,7 +80,7 @@ export const defaultToolbarStyles = theme => ({
 class TableToolbar extends React.Component {
   state = {
     iconActive: null,
-    showSearch: Boolean(this.props.searchText || this.props.options.searchText),
+    showSearch: Boolean(this.props.searchText || this.props.options.searchText || this.props.options.searchOpen),
     searchText: this.props.searchText || null,
   };
 

test/MUIDataTableToolbar.test.js

@@ -79,6 +79,16 @@ describe('<TableToolbar />', function() {
     assert.strictEqual(actualResult.props().options.searchText, 'searchText');
   });
 
+  it('should render a toolbar with search if option.searchOpen = true', () => {
+    const newOptions = { ...options, searchOpen: true };
+    const mountWrapper = mount(
+      <TableToolbar columns={columns} data={data} options={newOptions} setTableAction={setTableAction} />,
+    );
+    const actualResult = mountWrapper.find(TableSearch);
+    assert.strictEqual(actualResult.length, 1);
+    assert.strictEqual(actualResult.props().options.searchText, undefined);
+  });
+
   it('should render a toolbar with no search icon if option.search = false', () => {
     const newOptions = { ...options, search: false };
     const mountWrapper = mount(