The Godot-specific patch is just a single line now; removing this patch
will likely require adjusting Godot importer code to handle error limits
better.
This also adds new SIMPLIFY_ options; Godot is currently not using any
of these but might use SIMPLIFY_PRUNE and SIMPLIFY_SPARSE in the future.
Note: this change completely overwrites the meshoptimizer library source
(from git SHA c21d3be6ddf627f8ca852ba4b6db9903b0557858)
without including any patches; a distance error metric patch is still
needed and will be reapplied in the next commit.
The changes elsewhere are due to a signature change for
meshopt_simplifyWithAttributes.
-Reworked how meshes are treated by importer by using EditorSceneImporterMesh and EditorSceneImporterMeshNode. Instead of Mesh and MeshInstance, this allows more efficient processing of meshes before they are actually registered in the RenderingServer.
-Integrated MeshOptimizer
-Reworked internals of SurfaceTool to use arrays, making it more performant and easy to run optimizatons on.
