Recording data from BLE sensors alone (need to provide distance).

GPS is optional in this case, but no coordinates will be available.

Naive implementation tries to store data every second using the UI timer.

Part of #500.

src/main/java/de/dennisguse/opentracks/services/handlers/GPSHandler.java

@@ -158,6 +158,10 @@ public class GPSHandler implements LocationListener, GpsStatus.GpsStatusListener
         return lastTrackPoint;
     }
 
+    Distance getThresholdHorizontalAccuracy() {
+        return thresholdHorizontalAccuracy;
+    }
+
     /**
      * Called from {@link GpsStatus} to inform that GPS status has changed from prevStatus to currentStatus.
      *