Track recording service handles the status of recording: track's id, pause and GPS status.

Created an interface for all components that want to know about recording status through the service.
All interface's methods are optional so every component can implement what they need.
Fixes #388.

src/main/java/de/dennisguse/opentracks/io/file/importer/KmzTrackImporter.java

@@ -40,7 +40,6 @@ import de.dennisguse.opentracks.content.data.Track;
 import de.dennisguse.opentracks.content.provider.ContentProviderUtils;
 import de.dennisguse.opentracks.io.file.exporter.KmzTrackExporter;
 import de.dennisguse.opentracks.util.FileUtils;
-import de.dennisguse.opentracks.util.PreferencesUtils;
 
 /**
  * Imports a KMZ file.
@@ -79,7 +78,6 @@ public class KmzTrackImporter implements TrackImporter {
                 trackIdsWithImages.add(trackId);
                 deleteOrphanImages(context, trackId);
             } else {
-                cleanImport(context, trackId);
                 return new ArrayList<>();
             }
         }
@@ -230,18 +228,6 @@ public class KmzTrackImporter implements TrackImporter {
         }
     }
 
-    /**
-     * Cleans up import.
-     *
-     * @param trackId the trackId
-     */
-    private void cleanImport(Context context, Track.Id trackId) {
-        if (PreferencesUtils.isRecording(trackId)) {
-            ContentProviderUtils contentProviderUtils = new ContentProviderUtils(context);
-            contentProviderUtils.deleteTrack(context, trackId);
-        }
-    }
-
     private List<Track.Id> parseKml(ZipInputStream zipInputStream) {
         KmlFileTrackImporter kmlFileTrackImporter = new KmlFileTrackImporter(context);