CubeCamera: Add support for THREE.Layers.

src/cameras/CubeCamera.js

@@ -20,31 +20,37 @@ function CubeCamera( near, far, cubeResolution, options ) {
 	this.type = 'CubeCamera';
 
 	var cameraPX = new PerspectiveCamera( fov, aspect, near, far );
+	cameraPX.layers = this.layers;
 	cameraPX.up.set( 0, - 1, 0 );
 	cameraPX.lookAt( new Vector3( 1, 0, 0 ) );
 	this.add( cameraPX );
 
 	var cameraNX = new PerspectiveCamera( fov, aspect, near, far );
+	cameraNX.layers = this.layers;
 	cameraNX.up.set( 0, - 1, 0 );
 	cameraNX.lookAt( new Vector3( - 1, 0, 0 ) );
 	this.add( cameraNX );
 
 	var cameraPY = new PerspectiveCamera( fov, aspect, near, far );
+	cameraPY.layers = this.layers;
 	cameraPY.up.set( 0, 0, 1 );
 	cameraPY.lookAt( new Vector3( 0, 1, 0 ) );
 	this.add( cameraPY );
 
 	var cameraNY = new PerspectiveCamera( fov, aspect, near, far );
+	cameraNY.layers = this.layers;
 	cameraNY.up.set( 0, 0, - 1 );
 	cameraNY.lookAt( new Vector3( 0, - 1, 0 ) );
 	this.add( cameraNY );
 
 	var cameraPZ = new PerspectiveCamera( fov, aspect, near, far );
+	cameraPZ.layers = this.layers;
 	cameraPZ.up.set( 0, - 1, 0 );
 	cameraPZ.lookAt( new Vector3( 0, 0, 1 ) );
 	this.add( cameraPZ );
 
 	var cameraNZ = new PerspectiveCamera( fov, aspect, near, far );
+	cameraNZ.layers = this.layers;
 	cameraNZ.up.set( 0, - 1, 0 );
 	cameraNZ.lookAt( new Vector3( 0, 0, - 1 ) );
 	this.add( cameraNZ );