Rename widgets/wrappers.dart to widgets/basic.dart

Although the basic widgets are wrappers, that's an implementation detail and
shouldn't be encoded in the name of the library.

TBR=ianh@google.com

Review URL: https://codereview.chromium.org/1182983002.

examples/stocks2/lib/stock_app.dart

@@ -20,7 +20,7 @@ import 'package:sky/framework/widgets/radio.dart';
 import 'package:sky/framework/widgets/scaffold.dart';
 import 'package:sky/framework/widgets/tool_bar.dart';
 import 'package:sky/framework/widgets/ui_node.dart';
-import 'package:sky/framework/widgets/wrappers.dart';
+import 'package:sky/framework/widgets/basic.dart';
 
 import 'stock_data.dart';
 import 'stock_list.dart';

examples/stocks2/lib/stock_arrow.dart

@@ -8,7 +8,7 @@ import 'dart:sky' as sky;
 import 'package:sky/framework/rendering/box.dart';
 import 'package:sky/framework/rendering/object.dart';
 import 'package:sky/framework/theme2/colors.dart' as colors;
-import 'package:sky/framework/widgets/wrappers.dart';
+import 'package:sky/framework/widgets/basic.dart';
 
 class StockArrow extends Component {
 

examples/stocks2/lib/stock_list.dart

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:sky/framework/widgets/fixed_height_scrollable.dart';
-import 'package:sky/framework/widgets/wrappers.dart';
+import 'package:sky/framework/widgets/basic.dart';
 
 import 'stock_data.dart';
 import 'stock_row.dart';

examples/stocks2/lib/stock_menu.dart

@@ -4,7 +4,7 @@
 
 import 'package:sky/framework/widgets/checkbox.dart';
 import 'package:sky/framework/widgets/popup_menu.dart';
-import 'package:sky/framework/widgets/wrappers.dart';
+import 'package:sky/framework/widgets/basic.dart';
 import 'package:sky/framework/theme/view_configuration.dart';
 
 class StockMenu extends Component {

examples/stocks2/lib/stock_row.dart

@@ -7,7 +7,7 @@ import 'dart:sky' as sky;
 import 'package:sky/framework/rendering/box.dart';
 import 'package:sky/framework/theme2/typography.dart' as typography;
 import 'package:sky/framework/widgets/ink_well.dart';
-import 'package:sky/framework/widgets/wrappers.dart';
+import 'package:sky/framework/widgets/basic.dart';
 import 'package:sky/framework/rendering/paragraph.dart';
 
 import 'stock_arrow.dart';

examples/widgets/container.dart

@@ -5,7 +5,7 @@
 import 'package:sky/framework/rendering/box.dart';
 import 'package:sky/framework/rendering/flex.dart';
 import 'package:sky/framework/widgets/raised_button.dart';
-import 'package:sky/framework/widgets/wrappers.dart';
+import 'package:sky/framework/widgets/basic.dart';
 
 class ContainerApp extends App {
   UINode build() {

examples/widgets/hello_widgets.dart

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:sky/framework/widgets/wrappers.dart';
+import 'package:sky/framework/widgets/basic.dart';
 
 class HelloWorldApp extends App {
   UINode build() {

examples/widgets/spinning_mixed.dart

@@ -9,7 +9,7 @@ import 'package:sky/framework/rendering/flex.dart';
 import 'package:sky/framework/scheduler.dart';
 import 'package:sky/framework/widgets/raised_button.dart';
 import 'package:sky/framework/widgets/ui_node.dart';
-import 'package:sky/framework/widgets/wrappers.dart';
+import 'package:sky/framework/widgets/basic.dart';
 import 'package:vector_math/vector_math.dart';
 
 import '../lib/solid_color_box.dart';