Make use of new position access APIs for result marker highlighting
- switch highlight circles between "best location candidate" and "reference location" for consistency with AxfResult highlighting
Bugfixes in commits 0591de6a654b18cb8995e8528e07ed8aa267c414, 04a256940c80f0dc3ae555344cbfc7a55a499acc
- add missing "visible" parameter for the createMarker() call in drawCandidateMarkers()
- add missing thresholds in category() call in createMarker() for candidate markers