Update CardIOVideoStream's previewLayer to CALayer to allow it to be a SimulatedCameraLayer

Author: John Wisolith

Classes/CardIOVideoStream.mm

@@ -144,7 +144,7 @@ @interface CardIOVideoStream ()
 @property(nonatomic, assign, readwrite) BOOL wasRunningBeforeBeingBackgrounded;
 @property(nonatomic, assign, readwrite) BOOL didEndGeneratingDeviceOrientationNotifications;
 @property(assign, readwrite) UIInterfaceOrientation interfaceOrientation; // intentionally atomic -- video frames are processed on a different thread
-@property(nonatomic, strong, readwrite) AVCaptureVideoPreviewLayer *previewLayer;
+@property(nonatomic, strong, readwrite) CALayer *previewLayer;
 @property(nonatomic, strong, readwrite) AVCaptureSession *captureSession;
 @property(nonatomic, strong, readwrite) AVCaptureDevice *camera;
 @property(nonatomic, strong, readwrite) AVCaptureDeviceInput *cameraInput;