Rename editing2/ and theme2/ to editing/ and theme/.

Flesh out a README.md file for the SDK.
Make the stocks app test wait for the app to be mounted, to catch some more errors, like typos in the mount callback.

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1182053012.

examples/rendering/shadowed_box.dart

@@ -7,8 +7,8 @@ import 'dart:sky';
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/flex.dart';
 import 'package:sky/rendering/sky_binding.dart';
-import 'package:sky/theme2/colors.dart';
-import 'package:sky/theme2/shadows.dart';
+import 'package:sky/theme/colors.dart';
+import 'package:sky/theme/shadows.dart';
 
 void main() {
   var coloredBox = new RenderDecoratedBox(

examples/rendering/touch_demo.dart

@@ -10,7 +10,7 @@ import 'package:sky/rendering/object.dart';
 import 'package:sky/rendering/paragraph.dart';
 import 'package:sky/rendering/sky_binding.dart';
 import 'package:sky/rendering/stack.dart';
-import 'package:sky/theme2/colors.dart';
+import 'package:sky/theme/colors.dart';
 
 // Material design colors. :p
 List<Color> colors = [

examples/stocks2/lib/stock_arrow.dart

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

examples/stocks2/lib/stock_home.dart

@@ -2,9 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:sky/editing2/input.dart';
-import 'package:sky/theme2/colors.dart' as colors;
-import 'package:sky/theme2/typography.dart' as typography;
+import 'package:sky/editing/input.dart';
+import 'package:sky/theme/colors.dart' as colors;
+import 'package:sky/theme/typography.dart' as typography;
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/drawer.dart';
 import 'package:sky/widgets/drawer_header.dart';

examples/stocks2/lib/stock_row.dart

@@ -4,7 +4,7 @@
 
 import 'package:sky/painting/text_style.dart';
 import 'package:sky/rendering/box.dart';
-import 'package:sky/theme2/typography.dart' as typography;
+import 'package:sky/theme/typography.dart' as typography;
 import 'package:sky/widgets/ink_well.dart';
 import 'package:sky/widgets/basic.dart';
 

examples/stocks2/lib/stock_settings.dart

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:sky/theme2/colors.dart' as colors;
-import 'package:sky/theme2/typography.dart' as typography;
+import 'package:sky/theme/colors.dart' as colors;
+import 'package:sky/theme/typography.dart' as typography;
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/checkbox.dart';
 import 'package:sky/widgets/icon_button.dart';

examples/widgets/sector.dart

@@ -7,9 +7,9 @@ import 'dart:math' as math;
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/flex.dart';
 import 'package:sky/rendering/sky_binding.dart';
-import 'package:sky/theme2/colors.dart';
-import 'package:sky/theme2/edges.dart';
-import 'package:sky/theme2/typography.dart';
+import 'package:sky/theme/colors.dart';
+import 'package:sky/theme/edges.dart';
+import 'package:sky/theme/typography.dart';
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/material.dart';
 import 'package:sky/widgets/raised_button.dart';