Library version 1.8 around the corner

[indigoxela]

Seems to be a bigger change, so maybe updating the lib might be difficult.

Leaflet/Leaflet#7810

Needs thorough testing, for sure, but there's currently no build yet... We'll see.

[indigoxela]

And also: markercluster - check compatibility of its version 1.5.3 (https://www.cdnpkg.com/leaflet.markercluster)

[indigoxela]

It works! Apparently also all plugins. Only the widget has problems.

[indigoxela]

Re markercluster: There is a possible problem Leaflet/Leaflet.markercluster#1053, but that's not showing up with our current test setup (Leaflet 1.8.0-beta.0 and Markercluster 1.4.1+master.37ab9a2)

But with markercluster 1.5.3 an error similar to the widget one's appears: Uncaught TypeError: t is undefined

[indigoxela]

All plugins seem to work as expected. The widget causes some console nagging by leaflet.js, but still works ("wrong event specified: touchleave").

Markerclusters (also updated) seem to work fine.

The new css workaround for the pixel gap problem seems slightly better than the previous one.