TIANQI XIA

I fixed one bug and enhanced this part. Now it can search multiple boxes.

One simple solution for it (though not perfect): In src/layers/h3-hexagon-layer/h3-hexagon-layer.js, change `EnhancedColumnLayer` to `ColumnLayer`. (of course you need to `import ColumnLayer from '@deck.gl/layers/src/column-layer/column-layer';` at first. ) I did not check...

@ejrtn You may try my solution if you build kepler.gl by yourself.

One simple solution: you can first merge the geojsons / geo-dataframes together and distinguish them by adding one field. Then in the generated topojson dict, replace the single object by...