Move AppNavigation samples around

Move AppNavigation to SupportAppNavigation - this one uses the support
lib navigation helpers.

Add AppNavigation as an implementation of the same sample using the
framework features in JB.

Change-Id: I59e0f2e3e11ccccc277b177aee87bd88da8eb2c6
diff --git a/samples/AppNavigation/src/com/example/android/appnavigation/app/InterstitialMessageActivity.java b/samples/AppNavigation/src/com/example/android/appnavigation/app/InterstitialMessageActivity.java
index 1d0154d..c96995c 100644
--- a/samples/AppNavigation/src/com/example/android/appnavigation/app/InterstitialMessageActivity.java
+++ b/samples/AppNavigation/src/com/example/android/appnavigation/app/InterstitialMessageActivity.java
@@ -19,9 +19,9 @@
 import com.example.android.appnavigation.R;
 
 import android.app.Activity;
+import android.app.TaskStackBuilder;
 import android.content.Intent;
 import android.os.Bundle;
-import android.support.v4.app.TaskStackBuilder;
 import android.view.View;
 
 public class InterstitialMessageActivity extends Activity {