Object3D: Setting matrixWorldNeedsUpdate to false by default. Fixes #4506.

src/core/Object3D.js

@@ -35,7 +35,7 @@ THREE.Object3D = function () {
 	this.matrixWorld = new THREE.Matrix4();
 
 	this.matrixAutoUpdate = true;
-	this.matrixWorldNeedsUpdate = true;
+	this.matrixWorldNeedsUpdate = false;
 
 	this.visible = true;