added dzitilesource test module to coverage
added dzitilesource test module to coverage

rdlester/openseadragon,LarissaSmith/openseadragon,LarissaSmith/openseadragon,msalsbery/openseadragon,jmnetus/openseadragon,msalsbery/openseadragon,rdlester/openseadragon,avandecreme/openseadragon,seanich/openseadragon,seanich/openseadragon,openseadragon/openseadragon,jmnetus/openseadragon,openseadragon/openseadragon,avandecreme/openseadragon