Use constructor initializer list for Ray fields.

This improves the code generated by dart2js. 

Which in turn also allows V8 to figure out that `closeHitDistance` is property that always contains a number.
Merge pull request #9 from mraleph/master

Use constructor initializer list for Ray fields.
Added console-based C# native version
Merge pull request #10 from mdakin/master

Initial simd based version.
Merge branch 'master' of https://github.com/nippur72/Dart.RayTracerDemo