Handle subscription of messages in the webapp.

Messages larger than a threshold are split and reassembled due to the
size limit in webrtc. Threshold may have to be adjusted somewhere between
64KiB and 256KiB.

This also includes a basic handler for a ping message and a more
advanced image handler.

Change-Id: If66acfb1bb84e9d3ff686994a94b1480cb70b2aa
diff --git a/aos/network/www/index.html b/aos/network/www/index.html
index bc90d40..97e16d4 100644
--- a/aos/network/www/index.html
+++ b/aos/network/www/index.html
@@ -1,6 +1,11 @@
 <html>
-  <body>
+  <head>
     <script src="flatbuffers.js"></script>
-    <script src="proxy_bundle.min.js"></script>
+    <script src="main_bundle.min.js" defer></script>
+    <link rel="stylesheet" href="styles.css">
+  </head>
+  <body>
+    <div id="config">
+    </div>
   </body>
 </html>