* [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.
My implementation of AS_AT_LEAST_IOS9 broke when 8.4.1 was released.
I ran the iOS 9.0 simulator to find the proper `kCFCoreFoundationVersionNumber` value for iOS9, added this as `kCFCoreFoundationVersionNumber_iOS_9_0` and updated the `AS_AT_LEAST_IOS9` macro
Initial open-source release of ASMultiplexImageNode. Documentation and
example code forthcoming.
Note: ASMultiplexImageNode requires Xcode 6 to compile. Tests are now
compiled against the iOS 8 SDK and run on iOS 7.1 and iOS 8.
