* #39101: revert to compatibility fragments

There is an issue in a UI element (ViewPager), which does not get properly populated
when restoring its state. (found using VMs with API=16)
diff --git a/src/org/sflphone/fragments/MenuFragment.java b/src/org/sflphone/fragments/MenuFragment.java
index daa70b0..f83c4de 100644
--- a/src/org/sflphone/fragments/MenuFragment.java
+++ b/src/org/sflphone/fragments/MenuFragment.java
@@ -32,9 +32,10 @@
 
 import java.util.ArrayList;
 
-import android.app.LoaderManager;
-import android.content.AsyncTaskLoader;
-import android.content.Loader;
+import android.support.v4.app.Fragment;
+import android.support.v4.app.LoaderManager;
+import android.support.v4.content.AsyncTaskLoader;
+import android.support.v4.content.Loader;
 import org.sflphone.R;
 import org.sflphone.adapters.AccountSelectionAdapter;
 import org.sflphone.adapters.ContactPictureTask;
@@ -52,8 +53,6 @@
 import android.content.IntentFilter;
 import android.os.Bundle;
 import android.os.RemoteException;
-import android.provider.ContactsContract.Profile;
-import android.app.Fragment;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;