Implement Layout

```swift
var layoutManager: CALayoutManager?
The object responsible for laying out the layer’s sublayers.

func setNeedsLayout()
Invalidates the layer’s layout and marks it as needing an update.

func layoutSublayers()
Tells the layer to update its layout.

func layoutIfNeeded()
Recalculate the receiver’s layout, if required.

func needsLayout() -> Bool
Returns a Boolean indicating whether the layer has been marked as needing a layout update.

var autoresizingMask: CAAutoresizingMask
A bitmask defining how the layer is resized when the bounds of its superlayer changes.

func resize(withOldSuperlayerSize: CGSize)
Informs the receiver that the size of its superlayer changed.

func resizeSublayers(withOldSize: CGSize)
Informs the receiver’s sublayers that the receiver’s size has changed.

func preferredFrameSize() -> CGSize
Returns the preferred size of the layer in the coordinate space of its superlayer.
```