
Blender cannot be told to only allow absolute path for an RNA property (of type `string`, subtype `dir_path`), so as a workaround the final `render_output_path` is now using `bpy.path.abspath()` to make the path absolute. This has as advantage that the render output path can be defined by artists as a blendfile-relative path, and that it'll be resolved when submitting the blend file.