can't overwrite the iOS event.scale and found a hole in 'has'

src/utils.js

@@ -34,7 +34,7 @@ export function clone(obj) {
 }
 
 export function has(obj, prop) {
-	return obj && obj.hasOwnProperty(prop);
+	return obj && (obj.hasOwnProperty(prop) || (prop in obj));
 }
 
 export function hypotenuse(a, b) {