[importer] Use PG copy strategy in shp2pgsql wrapper
[importer] Use PG copy strategy in shp2pgsql wrapper

DigitalCoder/cartodb,raquel-ucl/cartodb,dbirchak/cartodb,UCL-ShippingGroup/cartodb-1,bloomberg/cartodb,codeandtheory/cartodb,codeandtheory/cartodb,nuxcode/cartodb,future-analytics/cartodb,thorncp/cartodb,bloomberg/cartodb,nyimbi/cartodb,codeandtheory/cartodb,thorncp/cartodb,nuxcode/cartodb,UCL-ShippingGroup/cartodb-1,splashblot/dronedb,nuxcode/cartodb,nyimbi/cartodb,codeandtheory/cartodb,future-analytics/cartodb,DigitalCoder/cartodb,dbirchak/cartodb,nyimbi/cartodb,raquel-ucl/cartodb,raquel-ucl/cartodb,dbirchak/cartodb,CartoDB/cartodb,splashblot/dronedb,CartoDB/cartodb,nuxcode/cartodb,CartoDB/cartodb,splashblot/dronedb,bloomberg/cartodb,future-analytics/cartodb,UCL-ShippingGroup/cartodb-1,splashblot/dronedb,raquel-ucl/cartodb,DigitalCoder/cartodb,dbirchak/cartodb,DigitalCoder/cartodb,UCL-ShippingGroup/cartodb-1,nyimbi/cartodb,bloomberg/cartodb,future-analytics/cartodb,CartoDB/cartodb,nyimbi/cartodb,raquel-ucl/cartodb,dbirchak/cartodb,codeandtheory/cartodb,nuxcode/cartodb,UCL-ShippingGroup/cartodb-1,CartoDB/cartodb,DigitalCoder/cartodb,thorncp/cartodb,future-analytics/cartodb,thorncp/cartodb,thorncp/cartodb,splashblot/dronedb,bloomberg/cartodb