Add more options for the importer

[luizcarlosfx]

The importer could have toggles to choose how to import some features:

• Bones
• Animations
• Combine primitives
• Materials
• Textures

In my case I don't want to import animations, nor bones. I added those options myself, but it's not that good since I want to receive your future updates without trouble. Also, your GLTFSceneImporter could be splited by module like (MaterialImporter, MeshImporter, HierarchyImporter, TextureImporter, AnimationImporter) that way it would be easier to maintain the code, the class now has 2000+ lines of code.

Thanks for the good work, you're doing an amazing job!

[sonygod]

good suggestion +1

[blgrossMS]

Thank you for the suggestion! We have a proposed architecture #259 that does show how we want to split the classes up easier. We may have some time coming up to implement it!

[pfcDorn]

Please update to the latest version. When you still missing some options, please open a new issue. Thanks!