Fixes#21364.
`self.Type` should be set in `__init__` and `loads`, and not in `onDocumentRestored`.
Additionally:
fixed mistake in `loads` in ifc_objects.py.
* BIM: Fix calculation of fence sections
The length and placement of fence sections was only correct if they were cut to size.
* Fix required another change.
* ShapeAppearance property was misspelled.
* The post and section objects could not be Std_Parts (because they do not have a DIffuseColor).
* Minor improvements to the handling of Bodies.
* Removed the `if __name__ == '__main__':` section. This code is no longer relevant.
