Make SkyElement more classy.

sky/examples/flights-app/flights-app.sky

 <import src="../../framework/sky-element/sky-element.sky" as="SkyElement" />
 <import src="app-header.sky" />
 <import src="app-title.sky" />
 <import src="app-menu-button.sky" />
 <import src="app-panel.sky" />
 <import src="app-panel-header.sky" />
 <import src="app-panel-content.sky" />
 <import src="app-toolbar.sky" />
 <import src="app-search-input.sky" />
 <import src="app-scrollable.sky" />
 <import src="app-toast.sky" />
 
+<sky-element name="flights-app">
 <template>
   <style>
     * { box-sizing: border-box; }
 
     t, span {
       display: inline;
     }
 
     :host {
       display: flex;
@@ skipping 170 matching lines @@
   <app-toast>
     <div class="toast-icon">
       <t>?</t>
     </div>
     <div class="toast-content">
       <t>Flights are <span class="tip-price">$200</span> cheaper tomorrow.</t>
     </div>
   </app-toast>
 </template>
 <script>
-SkyElement({
-  name: "flights-app",
-});
+module.exports = class extends SkyElement {
+}.register();
 </script>
+</sky-element>