Fix log splitting not showing logs with Marker

[JohannesRiegler]

Fixes #143

In the previous implementation there was a Nullpointer on calling addAll on the MarkerList

if (eventMarkers != null && !eventMarkers.isEmpty()) {
   logEventPartition.getMarkerList().addAll(eventMarkers);
}

This is now fixed, and the whole cloning logic was moved into the LoggingEventCloner