[Effen] basic layout container class for custom layout

sky/framework/components/fixed_height_scrollable.dart

Index: sky/framework/components/fixed_height_scrollable.dart
diff --git a/sky/framework/components/fixed_height_scrollable.dart b/sky/framework/components/fixed_height_scrollable.dart
index 0361ff1cda1311f1df60cc6561d83858f926e690..6a9f358004c1d5cefaa24832b3547865a2bf130a 100644
--- a/sky/framework/components/fixed_height_scrollable.dart
+++ b/sky/framework/components/fixed_height_scrollable.dart
@@ -9,6 +9,7 @@ import 'dart:math' as math;
 import 'dart:sky' as sky;
 import 'dart:async';
 import 'scrollable.dart';
+import '../layouts/block.dart';
 
 abstract class FixedHeightScrollable extends Scrollable {
   static final Style _style = new Style('''
@@ -84,7 +85,7 @@ abstract class FixedHeightScrollable extends Scrollable {
     return new Container(
       style: _style,
       children: [
-        new Container(
+        new BlockLayout(
           style: _scrollAreaStyle,
           inlineStyle: transformStyle,
           children: buildItems(itemNumber, drawCount)