Clean up examples directory

sky/examples/flights-app/app-menu-button.sky

Index: sky/examples/flights-app/app-menu-button.sky
diff --git a/sky/examples/flights-app/app-menu-button.sky b/sky/examples/flights-app/app-menu-button.sky
deleted file mode 100644
index 41709faed2fa99541997314ae64cb3a1a66646dd..0000000000000000000000000000000000000000
--- a/sky/examples/flights-app/app-menu-button.sky
+++ /dev/null
@@ -1,21 +0,0 @@
-<import src="../../framework/sky-element/sky-element.sky" as="SkyElement" />
-
-<sky-element name="app-menu-button">
-<template>
-  <style>
-    :host {
-      display: flex;
-      border-radius: 4px;
-      justify-content: center;
-      align-items: center;
-      width: 30px;
-      height: 30px;
-    }
-  </style>
-  <content></content>
-</template>
-<script>
-module.exports = class extends SkyElement {
-}.register();
-</script>
-</sky-element>