glTF Asset Importer

[tebjan]

Just because it's a recent hype and it looks like a nice open standard not dominated by a certain 3d software company:
https://github.com/KhronosGroup/glTF

[mafiesto4]

Xenko uses Assimp which supports importing some data from glTF (geometry and textures but animations are still WIP).

[xen2]

What needs to be done:

• check that the version of assimp we use is up to date enough to support this format (and upgrade assimp to latest version if too old)
• allow glTF file extension in model importer
• test it

[tebjan]

another option which supports animation: https://github.com/KhronosGroup/glTF-CSharp-Loader

[Eideren]

Mostly supported, I'll close this one off and leave #603 open to continue over there