use screenshots for tab switcher

    also removed the old tab switcher code

Change-Id: Id84ff64e42e5e1f70f55e136efdf84270c1a4b7b
diff --git a/res/layout/nav_tab_view.xml b/res/layout/nav_tab_view.xml
index 543c26e..05c91a0 100644
--- a/res/layout/nav_tab_view.xml
+++ b/res/layout/nav_tab_view.xml
@@ -48,11 +48,10 @@
             android:layout_width="wrap_content"
             android:layout_height="wrap_content" />
     </LinearLayout>
-    <FrameLayout
+    <ImageView
         android:id="@+id/tab_view"
         android:layout_width="@dimen/nav_tab_width"
         android:layout_height="@dimen/nav_tab_height"
         android:layout_gravity="center_horizontal"
-        android:focusable="false">
-    </FrameLayout>
+        android:focusable="false" />
 </LinearLayout>