Styling non-Points

[hylkevds]

I noticed it was not possible to style non-point Locations / Features when using Leaflet. I pushed a simple update that adds a config option to fix that. I've not checked if it is an issue in OpenLayers as well though.

[hylkevds]

@TobiasPressler can you have a look at the commit, does it match your design ideas? :)

[hylkevds]

I just noticed that the count-squares are added to the same layer as the Locations/Features, so the styling function is currently also called for them.

I also noticed that the styling function is re-called for every "update" tick of the L.realtime layer (currently every 300 milliseconds), which is also not ideal.

[TobiasPressler]

So maybe add a wrapper function that caches the styling?