Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1259
Wires C ABI to C# bindings using `System.Runtime.InteropServices`. Note that we don't have a working C# build right now, but there is [effort to address that](https://github.com/facebook/yoga/pull/1207) which may get some more effort before the Yoga release, so this keeps the bindings up to date.
Reviewed By: yungsters
Differential Revision: D45297676
fbshipit-source-id: 10cfb71a6220e4c7a6fc15032cd74033d4472f4b
10bf9f11fd