Add options and a browser-action popup.

go-back-with-backspace/pages/installed.css

Index: go-back-with-backspace/pages/installed.css
diff --git a/go-back-with-backspace/pages/installed.css b/go-back-with-backspace/pages/installed.css
new file mode 100644
index 0000000000000000000000000000000000000000..10f24fe2a70d3373869c9c0125e094c1672da10c
--- /dev/null
+++ b/go-back-with-backspace/pages/installed.css
@@ -0,0 +1,21 @@
+/**
+ * Copyright 2016 Google Inc. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+body {
+  direction: __MSG_@@bidi_dir__;
+}
+
+#icon {
+  float: __MSG_@@bidi_start_edge__;
+}
+
+#notes {
+  margin-top: 40px;
+}
+
+#button_div {
+  margin-top: 10px;
+}