Fix subcluster list for event-display #45
Description
Currently the subcluster list in code.js is manually entered.
And it excludes all subclusters with one or no stations.
This is because I had trouble with Leaflet showing a map when there was only one coordinate. - Fixed in f7787aa
Also a problem for enschede. It works, but the map is initially gray, until you zoom.
Perhaps also create a clusters.json to dynamically load the appropriate cluster names.