CatmullRomCurve3: .closed is false instead of undefined by default

src/extras/curves/CatmullRomCurve3.js

@@ -84,6 +84,7 @@ THREE.CatmullRomCurve3 = ( function() {
 		function ( p /* array of Vector3 */ ) {
 
 			this.points = p || [];
+			this.closed = false;
 
 		},