SwiftUI Support

New features:

• Add SwiftUI support
• ZPosition can be handled via CALayer or layout attribute or both, see CollectionViewPagingLayout.zPositionHandler
• ViewAnimator: You can set the animation duration or implement your custom animator.
• You can use the predefined layout options using an enum. for instance, ScaleTransformViewOptions.Layout.coverFlow
• SnapshotTransformView.canReuse(snapshot:) You can define when the existing snapshots invalidate.

Changes:

• By default, zIndex will apply to the attribute and the CALayer, you can change it using CollectionViewPagingLayout.zPositionHandler
• configureTapOnCollectionView and didSelectItemAt methods removed. You can use the built-in collectionview delegate instead!
• Fix a problem: a page blinks before the transform effects apply on it, to fix it the attributes have alpha=0 by default before the cell is loaded. You can change it by setting "transparentAttributeWhenCellNotLoaded" to false
• An bounds observer added for the collection view so, you don't need to call "invalidateLayout" on "viewDidLayoutSubviews"
• If you are on page 1 and call setCurrentPage(4). the delegate method only gets called for page 4. previously, it was 2,3 and 4
• ScaleTransformView.blurHost renamed to ScaleTransformView.scaleBlurHost
• StackTransformView.blurHost renamed to StackTransformView.stackBlurHost
• SnapshotTransformView.identifier renamed to SnapshotTransformView.snapshotIdentifier
• Change default implementation of snapshotIdentifier to consider contentOffset of a possible scrollview inside a page