* added a fix for BlueprintInfo path issues on non posix platform by replacing specific
os.path.join calls with posixpath.join ones (blueprint info paths, export_path, material_path etc)
should hopefully solve spawning issues on Windows
* restructured & improved materials export: now uses same logic as blueprints, with seperate determining of
what materials changed & the export itself
* minor tweaks
* fixed issue with parenting due to Blender's very weird matrix_parent_inverse ... solves all issues with children of empties
blueprint instances within blueprint instances etc having the wrong transforms in some cases
* fixed bad gltf format propagation: semi ok solution, but a cleaner one would be better
* added additional custom properties to the blacklist , level/blueprint exports are now using the one in the constants
instead of a local copy
* minor tweaks & cleanups
* split out materials scan from injection of materialInfo into objects
* added material Asset injection into list of assets at scene level
* related tweaks & cleanups
* continued overhaul on the bevy side
