Fix IfcOpenShell#2828. Extending walls to roofs / slabs is now more i…

…ntuitive as you select the target slab last.

A last bit of cleaning up temp files after tests

By default, the site is now cut with a nice thick line on drawings

Minor fix

Minor fix

Fix IfcOpenShell#2808. Bug where you couldn't assign element types in…

… IFC4X3.

Monolithic stair variant generator

Fix IfcOpenShell#2424. Bug where indirect assets (e.g. importing a ty…

…pe using a material) with relationships had their relationships duplicated

Fix IfcOpenShell#2442. Fix bug where viewboxes were not clipped when …

…compiling drawing sheets.

Fix IfcOpenShell#2767. Removing representations now cleans up after o…

…rphaned Blender mesh data.