Improve the RenderObject.toString() logic so that there's not blank lines everywhere and to general…

sky/examples/stocks2/lib/stock_app.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'package:sky/framework/components2/tool_bar.dart';
 import 'package:sky/framework/components2/drawer.dart';
 // import 'package:sky/framework/components2/drawer_header.dart';
 // import 'package:sky/framework/components2/floating_action_button.dart';
 // import 'package:sky/framework/components2/icon.dart';
 import 'package:sky/framework/components2/icon_button.dart';
@@ skipping 203 matching lines @@
         drawer: _drawerShowing ? buildDrawer() : null
       ),
     ];
     addMenuToOverlays(overlays);
     return new StackContainer(children: overlays);
   }
 }
 
 void main() {
   print("starting stocks app!");
-  new StocksApp();
+  App app = new StocksApp();
+  app.appView.onFrame = () {
+    // uncomment this for debugging:
+    // app.appView.debugDumpRenderTree();
+  };
 }