* bumped up Bevy version to v0.14 !
* fixed (albeit in a clunky way) issues with sub blueprint detection
* improved error message for missing material library
* added HideUntilReady component & logic, to hide 'in-spawning' blueprint instances until they are ready
* "add-to-world" is now only trigerred for blueprint instances that have no parents (avoid footgun)
* minor cleanups & tweaks
* added test component with Vec3 to double check for issues
* updated test blend file to include the component above + added a light to the test spawnable blueprint
to check for "light flashes" (aka indirectly testing "HideUntilReady")
* updated simple test to include deep nested blueprint instance within blueprint instance case
* restructured materials handling to use the new logic, removed clutter
* experimenting with solutions to the deeply nested blueprint instances problem
* moved out all obsolete code to "old" folder, keeeping around until all problems are solved
* added hack-ish solution to the "aabb system as post process" implementation
* various minor boilerprate changes
* added logic to track spawning of sub blueprints
* added ability to determine when a blueprint instance is truly ready
(aka all its assets have been loaded, blueprint scene & sub scenes spawned & processed etc)
* reworked spawning steps for more determinism & reliability
* no more "seperate" spawning post process
* lots of related changes
* still messy but functional
* Blender: some additional component filtering for upgrade ui
* Bevy:
* experimenting with overhauled blueprint spawning logic, sub-blueprint instance tracking etc
* added a more simple blend file to test things out with
* added additional test "upgreadeable components"
* added test "buggy" hierarchies: blueprint instances as children of empties and blueprint
instances as children of other blueprint instance
* more materials
* testing cases for various levels of nesting/ targets for components
* reorganized objects in 3d scene for more clarity
* changed camera view for more clarity
* added background color & filmic
