Make SkyElement more classy.

sky/examples/flights-app/app-search-input.sky

 <import src="../../framework/sky-element/sky-element.sky" as="SkyElement" />
+
+<sky-element name="app-search-input">
 <template>
   <style>
     :host {
       background-color: #F6F6F6;
       padding: 4px;
       display: flex;
       align-items: center;
       font-size: 1.2em;
     }
 
     .input-text {
       margin-left: 8px;
     }
   </style>
   <span class="input-icon">
     <img src="/sky/examples/flights/images/magnifying-glass.png" style="width: 16px">
   </span>
   <span class="input-text"><t>flights today to dc by price</t></span>
 </template>
 <script>
-SkyElement({
-  name: "app-search-input"
-});
+module.exports = class extends SkyElement {
+}.register();
 </script>
+</sky-element>