Allow Effen Styles to be extendable

sky/framework/editing/editable_text.dart

Index: sky/framework/editing/editable_text.dart
diff --git a/sky/framework/editing/editable_text.dart b/sky/framework/editing/editable_text.dart
index df73e46262334c72669827fe82d9bf4fdf3b6904..5a0b0810d10c24e941dbb125997529d067995d87 100644
--- a/sky/framework/editing/editable_text.dart
+++ b/sky/framework/editing/editable_text.dart
@@ -75,8 +75,8 @@ class EditableText extends Component {
       String composing = value.textInside(value.composing);
       if (!composing.isEmpty) {
         children.add(new Container(
-          key: 'composing', 
-          styles: [_composingStyle],
+          key: 'composing',
+          style: _composingStyle,
           children: [new Text(composing)]
         ));
       }
@@ -87,10 +87,10 @@ class EditableText extends Component {
     }
 
     if (_showCursor)
-      children.add(new Container(key: 'cursor', styles: [_cusorStyle]));
+      children.add(new Container(key: 'cursor', style: _cusorStyle));
 
     return new Container(
-      styles: [_style],
+      style: _style,
       children: children
     );
   }