SkeletonJson.readVertices doesn't read vertices

[jeremyfa]

When trying to implement mesh rendering, I ran into this piece of code:

https://github.com/bendmorris/spinehaxe/blame/master/spinehaxe/SkeletonJson.hx#L282-L293

At the moment, some portion of the code is commented and vertices are always empty, making mesh rendering completely unusable.