Mesh export does not work in Blender 4.1 onward

[FwiffoForce]

Blender v. 4.1 removed the create_normals_split function from the Python API. Because of this, attempting to export a mesh object now throws an exception, causing no file to be generated.

Reverting to version 4.0 or earlier fixes the issue, but that is not an ideal solution. The scripting should be updated to function with the new API.

[Calinou]

See #133 (comment).