add "clipPath" to unsupported elements
add "clipPath" to unsupported elements

tomhughes/mapnik,lightmare/mapnik,tomhughes/mapnik,naturalatlas/mapnik,mapnik/mapnik,tomhughes/mapnik,lightmare/mapnik,lightmare/mapnik,naturalatlas/mapnik,tomhughes/mapnik,lightmare/mapnik,naturalatlas/mapnik,naturalatlas/mapnik,mapnik/mapnik,mapnik/mapnik,mapnik/mapnik