This update mainly focuses on BO3 export workflow improvements, GDT creation, material conversion, and fixes for newer-game animation exports.

GDT Creation:
- Creates xmodel entries
- Creates xanim entries
- Creates material entries for exported models
- Creates image entries for material textures
- Assigns BO3 material types based on the textures available
- Links xanim entries to exported models where possible
- Supports game-aware GDT output, so exports from the same game can be added to the same GDT
- Added optional separate GDT per export mode

Material / Texture Improvements:
- Added Unreal packed texture handling for ORM/spec-mask style maps
- Converts packed maps into BO3-friendly AO, gloss, and spec maps
- Missing normal maps now use `$identitynormalmap`
- Missing AO maps now use `$occlusion`
- Improved diffuse/color image GDT setup
- Improved emissive material setup
- Improved Fortnite spec/gloss handling

Fortnite Layered Material Support:
- Added Fortnite layered material fixes
- Models using layered materials can now be split into separate BO3 materials
- Layered materials are assigned to the correct mesh faces where possible

Fixes:
- Fixed Cast exports for models and animations
- Fixed BL3 animation export for XANIM and Cast
- Fixed XMODEL/export transform issues that caused animated mesh parts to separate or fly away
- Fixed BO3 xanim GDT entries to use the proper relative animation setup
- Improved large batch exporting so the UI should freeze less when queueing lots of models

Notes:
- GDT creation is still WIP and will keep improving as more games/material edge cases are tested.
- For GDT creation, export paths need to be inside the Black Ops III folder so generated paths work correctly.