* [ASCornerRounding] Initial (untested) implementation of ASCornerRounding features.
* [ASCornerRounding] Working version of both clip corners and precomposited corners.
* [ASCornerRounding] Improve factoring and documentation of corner rounding features.
* [ASCornerRounding] Some final fixups.
* Add entry to changelog for .cornerRoundingType
* Notify rasterized subsides that render pass has completed
* Traverse entire subnode tree notifying all subnodes
* Add entry in changelog
* Retrieve rasterizesSubtree flag while holding instance lock
* Balance display delegate calls for rasterized subnodes
This makes it much easier to use the ASCoreAnimationExtras method which offers by
far the most efficient way to display a stretchable image.
In the future, we should move that function to UIImage+ASConvenience or another
header where it can be more easily found and enjoyed!
