rename global

Summary:
global variable was renamed from `Sonar` to `Flipper`.

Fixes #267.

Reviewed By: passy

Differential Revision: D9934362

fbshipit-source-id: 0c03f3e12d9db26c5c7e9430fc98ba7fffd0bf54

static/index.dev.html

@@ -86,7 +86,7 @@
           };
 
           script.onload = () => {
-            global.Sonar.init();
+            global.Flipper.init();
           };
 
           document.body.appendChild(script);

static/index.html

@@ -15,7 +15,7 @@
     </script>
     <script src="bundle.js"></script>
     <script>
-      global.Sonar.init();
+      global.Flipper.init();
     </script>
   </body>
 </html>