gui: UI improvements

- Make use of addHeaderView of ListViews, instead of using embedded
  ListViews
- Use action bar icons as an entry point for settings, refresh, and add
  functions

Change-Id: I6db1cf1a84271a224cf777e06262380afca49709
diff --git a/app/src/main/res/menu/menu_logcat_settings.xml b/app/src/main/res/menu/menu_logcat_settings.xml
new file mode 100644
index 0000000..86679ea
--- /dev/null
+++ b/app/src/main/res/menu/menu_logcat_settings.xml
@@ -0,0 +1,12 @@
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <item
+        android:id="@+id/action_log_settings"
+        android:icon="@drawable/ic_action_edit"
+        android:title="@string/logcat_reset_log_level_defaults"
+        android:orderInCategory="100"
+        app:showAsAction="always"
+        />
+
+</menu>