Arch objects can now be based on a Part Compound and will take
its DiffuseColor property. Arch objects that are clones of
such objects will also copy that property.
* 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
