fix pngExport with new kineticjs
fix pngExport with new kineticjs

bhargav175/mapjs,bhargav175/mapjs,AbdulMuhsinSE/mapjs,danielrasmuson/mapjs,mindmup/mapjs,AbdulMuhsinSE/mapjs,danielrasmuson/mapjs,bhargav175/mapjs,mindmup/mapjs,AbdulMuhsinSE/mapjs,danielrasmuson/mapjs,pyxis777/mapjs,pyxis777/mapjs,pyxis777/mapjs