Support for KHR_materials_pbrSpecularGlossiness in glTF importer

[zen253230]

Hello and thank you for all the corrections you made for gltf loading.

This time it is about a file with unsupported extensions KHR_materials_common : https://github.com/xeolabs/xeogl/tree/master/examples/models/gltf/ReciprocatingSaw/glTF-MaterialsCommon

Question is whether it should load even while showing the error???

The same file in : https://github.com/xeolabs/xeogl/tree/master/examples/models/gltf/ReciprocatingSaw/glTF-pbrSpecularGlossiness loads perfectly, So is it a problem of special file...?

Thank you for your patience

[kovacsv]

https://kcoley.github.io/glTF/extensions/2.0/Khronos/KHR_materials_pbrSpecularGlossiness/