Reason: in a future port to GDExtension, that class won't be available.
This may also apply to Map and HashMap.
Note: the issues in streams were not hit so far because they are in
multi-block load/save functions. We've been loading and saving blocks
one by one at the moment.
- Made a bunch of changes to comply with Godot 4 API
- Use Godot's Vector3i and add the missing stuff with helper functions
- Transvoxel uses custom attributes API, the old way would not work
- Wrap MeshOptimizer in a unique namespace (see build script why)
- Added clang-format file for the module as some rules now differ
- Prevent thirdparty code and lookup tables from being clang-formatted
- Very likely full of runtime bugs that need fixing
