make coverage loader more robust for invalid geometries
make coverage loader more robust for invalid geometries

camptocamp/mapproxy,vrsource/mapproxy,kaiCu/mapproxy,vrsource/mapproxy,procrastinatio/mapproxy,geoadmin/mapproxy,camptocamp/mapproxy,procrastinatio/mapproxy,mapproxy/mapproxy,mapproxy/mapproxy,olt/mapproxy,olt/mapproxy,drnextgis/mapproxy,drnextgis/mapproxy,geoadmin/mapproxy,kaiCu/mapproxy