* 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
478be88a55