Leafletdefaulticoncompatibility

Retrieve all Leaflet Default Icon options from CSS, in particular all icon images URL's, to improve compatibility with bundlers and frameworks that modify URL's in CSS. In particular for webpack (with style-, css-, file- and url-loader's), Rails Asset Pipeline and Django pipeline. Should solve all use cases linked to <a href="https://github.com/Leaflet/Leaflet/issues/4968">issue Leaflet/Leaflet #4968</a>. <a href="https://ghybs.github.io/leaflet-defaulticon-compatibility/webpack-demo.html">Demo with webpack</a> (and <a href="https://ghybs.github.io/leaflet-defaulticon-compatibility/webpack-demo.html?demo=no-plugin">without this plugin</a>).