Using the "smart merge" method results is map being merged but the map shown to
the user is still the one downloaded in the beginning, not reloading
leads to conflict in the following save

cf umap-project/umap#423

fix umap-project/umap#434

fix umap-project/umap#436

fix umap-project/umap#393

And there is not npm stable release. Let's not depend on a third party
git trunk.

Update Mocha link

cf umap-project/umap#418

They visually conflict with the Leaflet tooltip.

fix umap-project/umap#413