Add an option not to clip features if they appear in the tile at all

tests/curve/in.json

@@ -0,0 +1 @@
+{"type":"FeatureCollection","features":[{"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[-99,83],[-117,71],[-118,26],[-97,-38],[-75,-66],[-33,-77],[93,-79],[145,-77],[145,-74],[90,-74],[-28,-73],[-63,-63],[-82,-33],[-103,32],[-106,70],[-82,82],[-99,83]]]}}]}