add shield-transform, shield-placements, and shield-placement-type
add shield-transform, shield-placements, and shield-placement-type

mapnik/mapnik-reference,mapycz/mapnik-reference,florianf/mapnik-reference,gravitystorm/mapnik-reference,mojodna/mapnik-reference,mojodna/mapnik-reference,gravitystorm/mapnik-reference,CartoDB/mapnik-reference,florianf/mapnik-reference,CartoDB/mapnik-reference,mapycz/mapnik-reference,mapnik/mapnik-reference,mapnik/mapnik-reference