Sample file that demonstrates the use of animation pointers and texture transform

[andybak]

I've tried the only two I can find:

https://github.com/KhronosGroup/glTF-Sample-Assets/tree/PotOfCoalsAnimationPointer/Models/PotOfCoalsAnimationPointer/glTF-Binary

https://github.com/KhronosGroup/glTF-Sample-Assets/blob/AnimationPointerUVs/Models/AnimationPointerUVs/glTF-Binary/

and neither seem to work with latest HEAD (as of 15 hours ago from the time of this post)

[hybridherbst]

Animation Pointer sample files are still stuck in this PR: KhronosGroup/glTF-Sample-Assets#106, you can grab them from there for testing.

@pfcDorn please take a look as to why the above file doesn't import properly – thanks!