Arch: Misc improvements for IFC workflow

* Added utility to make non-parametric Arch component
* Ability for all Arch components to be a clone of another Arch component of same type
* Modified the Draft Clone tool to produce Arch Clones if applicable
* Fixed Arch Roofs so they can be based on a solid shape like other Arch objects
* Ability to change the Root element to be imported in IFC preferences
* Ability to import IFC files also as compounds, Part shapes or non-parametric Arch objects
* Added an "only" parameter to importIFC.open() to import only a certain object ID.
* Ability to read colors (IfcSurfaceStyle) from IFC objects

src/Mod/Arch/ArchStructure.py

@@ -577,6 +577,9 @@ class _Structure(ArchComponent.Component):
         "creates the structure shape"
 
         import Part, DraftGeomUtils
+        
+        if self.clone(obj):
+            return
 
         normal,length,width,height = self.getDefaultValues(obj)