Request to add PruneCluster

[Neato-Nick]

This plug-in allows many features, including real-time updates to marker clusters and interfacing with categories to create donut graphs on marker clusters

https://github.com/SINTEF-9012/PruneCluster

[trafficonese]

There’s already a branch in leaflet.extras2 for this plugin, but I didn’t quite finish it:
https://github.com/trafficonese/leaflet.extras2/tree/prunecluster

The main issue back then was that the categories were hardcoded to 0–7, so I had to map the R categories onto numeric values in that range.

I also left an example app here:
https://github.com/trafficonese/leaflet.extras2/blob/prunecluster/inst/examples/pruneCluster_app.R

Feel free to take a look, test it, or extend it if you’d like 🙂