* [ASCollectionView] Add delegate bridging and index space translation for missing UICollectionViewLayout properties
This is a first attempt at resolving #438.
I know there is already one similar method to do indexPath conversions, and that the #define for
accessing properties on the UICollectionViewFlowLayout should probably be moved somewhere else.
Looking for feedback on the general direction here. In particular, I'm a bit surprised that so much
has changed in how these calls occur, as I believe especially constrainedSizeForNodeAtIndexPath: is
now called with inconsistent index path spaces (but was not before this PR landed in March:
https://github.com/facebookarchive/AsyncDisplayKit/pull/3136/files)
Since the impact of mixing the spaces is fairly serious (can cause crashes), I'm also wondering if
I am misinterpreting some aspects of the code, or if maybe the crashing impact wasn't noticed yet.
* [ASCollectionView] Cleanup and final changes for UIKit passthrough fixes.
