prevent ImportError during test when mapnik is missing
prevent ImportError during test when mapnik is missing

mapproxy/mapproxy,procrastinatio/mapproxy,vrsource/mapproxy,drnextgis/mapproxy,geoadmin/mapproxy,mapproxy/mapproxy,procrastinatio/mapproxy,camptocamp/mapproxy,Anderson0026/mapproxy,faegi/mapproxy,faegi/mapproxy,vrsource/mapproxy,kaiCu/mapproxy,Anderson0026/mapproxy,drnextgis/mapproxy,camptocamp/mapproxy,olt/mapproxy,kaiCu/mapproxy,geoadmin/mapproxy,olt/mapproxy