Organize sky/framework a bit

sky/framework/sky-scrollable.sky

 <!--
 // 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 src="sky-element.sky" />
 
 <sky-element>
 <template>
   <style>
@@ skipping 19 matching lines @@
   }
   </style>
   <div id="scrollable">
     <content />
   </div>
   <div id="vbar" />
 </template>
 <script>
 import "dart:math" as math;
 import "dart:sky";
-import "fling-curve.dart";
-import "view-configuration.dart" as config;
+import "animation/fling-curve.dart";
+import "theme/view-configuration.dart" as config;
 
 @Tagname('sky-scrollable')
 class SkyScrollable extends SkyElement {
   Element _scrollable;
   Element _vbar;
   double _scrollOffset = 0.0;
   FlingCurve _flingCurve;
   int _flingAnimationId;
 
   SkyScrollable() {
@@ skipping 101 matching lines @@
   }
 
   void _handleWheel(WheelEvent event) {
     scrollBy(-event.offsetY);
   }
 }
 
 _init(script) => register(script, SkyScrollable);
 </script>
 </sky-element>