Move sky-*.sky into framework/elements

sky/examples/stocks/stocks.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/framework/sky-drawer-header.sky" />
-<import src="/sky/framework/sky-drawer.sky" />
-<import src="/sky/framework/sky-element.sky" />
-<import src="/sky/framework/sky-icon.sky" />
-<import src="/sky/framework/sky-menu-divider.sky" />
-<import src="/sky/framework/sky-menu-item.sky" />
-<import src="/sky/framework/sky-scrollable.sky" />
-<import src="/sky/framework/sky-toolbar.sky" />
+<import src="/sky/framework/elements/sky-drawer-header.sky" />
+<import src="/sky/framework/elements/sky-drawer.sky" />
+<import src="/sky/framework/elements/sky-element.sky" />
+<import src="/sky/framework/elements/sky-icon.sky" />
+<import src="/sky/framework/elements/sky-menu-divider.sky" />
+<import src="/sky/framework/elements/sky-menu-item.sky" />
+<import src="/sky/framework/elements/sky-scrollable.sky" />
+<import src="/sky/framework/elements/sky-toolbar.sky" />
 <import src="stock.sky" as='view'/>
 
 <sky-element>
 <template>
   <style>
     :host {
       display: flex;
       flex-direction: column;
       height: -webkit-fill-available;
       font-family: 'Roboto Regular', 'Helvetica';
@@ skipping 79 matching lines @@
   }
 
   void _handleMenuClick(_) {
     _drawer.toggle();
   }
 }
 
 _init(script) => register(script, Stocks);
 </script>
 </sky-element>