* [Yoga + AsyncDisplayKit] Initial commit for supporting Yoga-powered layout calculation.
Because this results in ASLayout objects, it preserve support for automaticallyManagesSubnodes
as well as the animated transition system. More work remains to vet performance of the new mode,
and it will remain in +Beta for the forseeable future.
I'm not sure that this should ever be used as the primary ASDK layout system, but it should remain an
option for some apps to experiment with if they require an implementation that more strictly mirrors
W3C standard Flexbox.
* [Yoga] Improve usage of ASHierarchyState to ensure simultaneous yoga layouts can't happen.
* [Yoga] Strictly minimize the impact of the Yoga integration on existing code.
Created new file ASDisplayNode+Yoga.mm, reduced size and number of integration points in core code.
* [Yoga] Figured out how to further reduce ASDisplayNode.mm impact by allocating _yogaNode in property accessor, and changing all accesses to use the property.
* Reimplement IGListKit support in a cleaner way
* Rename and fix some stuff
* Fix supplementaries more
* Update docs
* Update test
* Cleanup minor things
* Tweak it
* Indentation
* Remove irrelevant changes
* Break out cell into its own file
* Fix indentation
* Address feedback
