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/androidTest/java/de/dennisguse/opentracks/services/handlers/TrackPointCreatorTest.java

@@ -3,7 +3,6 @@ package de.dennisguse.opentracks.services.handlers;
 import static org.mockito.Mockito.verify;
 
 import android.content.Context;
-import android.content.SharedPreferences;
 
 import org.junit.After;
 import org.junit.Before;
@@ -28,9 +27,6 @@ public class TrackPointCreatorTest {
     @Mock
     private GPSHandler locationHandler;
 
-    @Mock
-    private SharedPreferences sharedPreferences;
-
     private TrackPointCreator subject;
 
     @Before