TrackListActivity: removed start/stop GPS toast message.

Nowadays, we already have a notification in place.

src/main/java/de/dennisguse/opentracks/TrackListActivity.java

@@ -28,7 +28,6 @@ import android.location.LocationManager;
 import android.os.Bundle;
 import android.provider.Settings;
 import android.util.Log;
-import android.view.Gravity;
 import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuItem;
@@ -382,11 +381,6 @@ public class TrackListActivity extends AbstractListActivity implements ConfirmDe
                 } else {
                     startGps = !ServiceUtils.isTrackRecordingServiceRunning(this);
 
-                    // Show toast
-                    Toast toast = Toast.makeText(this, startGps ? R.string.gps_starting : R.string.gps_stopping, Toast.LENGTH_SHORT);
-                    toast.setGravity(Gravity.CENTER, 0, 0);
-                    toast.show();
-
                     // Invoke trackRecordingService
                     if (startGps) {
                         trackRecordingServiceConnection.startAndBind(this);