Summary:
- Does not contain "magic" found in YogaKit yet, but enough to get started
- Simple test project showing use
- YGInteropSetLogger and YGNodeInit(IntPtr) were missing from native lib built by buck
Closes https://github.com/facebook/yoga/pull/278
Reviewed By: emilsjolander
Differential Revision: D4388480
Pulled By: splhack
fbshipit-source-id: a7387bb5b5554b6fce80d08c23e4fa18a4611cce
