Add time-range directive to the demo page

Author: g1eb

index.html

@@ -30,6 +30,17 @@ <h1>Date</h1>
     on-close="closed()">
   </date-range>
 
+  <h1>Time</h1>
+  <time-range
+    start="start"
+    end="end"
+    presets="presets"
+    on-change="changed()"
+    on-change-start="changedStart()"
+    on-change-end="changedEnd()"
+    on-close="closed()">
+  </time-range>
+
   <h1>Datetime</h1>
   <datetime-range
     start="start"