Fix Firefox flickering on mouse over geocoder
Fix Firefox flickering on mouse over geocoder

Using the events `mouseenter`, `mouseleave` applies the `L.DomEvent.isExternalTarget` check, which tests if element really left/entered the event target.

Fixes #174.

perliedman/leaflet-control-geocoder,wbg/leaflet-control-geocoder,perliedman/leaflet-control-geocoder,wbg/leaflet-control-geocoder,perliedman/leaflet-control-geocoder,wbg/leaflet-control-geocoder