v1.9.3

• engine: Added new APIs to enable/disable screen space refraction
• engine: Fix, flip the shading normal when det < 0.
• gltfio: Fix animation by clamping the per-channel interpolant.
• gltfio: add async cancellation API
• gltfio: Fix "uniform not found" errors.
• gltfio: Disable clear coat layer IOR change in glTF files (#3104)
• Vulkan: fix final image barrier used for swap chain.
• matdbg: Various improvements
• JavaScript bindings: fix TextureUsage bitmask.
• cmgen / mipgen: add opt-in for ASTC / ETC support.