Caches textures to disk for shape formats that support embedded textures.
Only the compressed texture codepath has been tested. There are a large number of binary gltf files with embedded (and pbr) textures for testing here: https://github.com/KhronosGroup/glTF-Sample-Models
The lodType, singleDetailSize, adjustCenter and adjustFloor options been added to the importer.
Implementation of $Assimp::FlipNormals has been fixed.
$Assimp::FlipWindingOrder has been added to expose aiProcess_FlipWindingOrder.
Logging is now enabled and directed to assimp.log.
