UV_OT_export_layout: Workaround to make the addon register

__name__ is never "__main__" here, but instead it is the module name (io_mesh_uv_layout).

io_mesh_uv_layout/__init__.py

@@ -301,14 +301,14 @@ def menu_func(self, context):
 
 
 def register():
-    bpy.utils.register_module(__name__)
+    bpy.utils.register_class(ExportUVLayout)
     bpy.types.IMAGE_MT_uvs.append(menu_func)
 
 
 def unregister():
-    bpy.utils.unregister_module(__name__)
+    bpy.utils.unregister_class(ExportUVLayout)
     bpy.types.IMAGE_MT_uvs.remove(menu_func)
 
 
-if __name__ == "__main__":
+if __name__ == 'io_mesh_uv_layout':
     register()