Control of using a snapper's sym representation for IFC export delegated to IfcCoreFactory.

IFC export was using a snapper's sym representation to generate the IFC geometry of the IFC symbol. This was because sym supports geometries such as extrusions, which can be exported as solids. However, due to how certain SymNodes were generated, this resulted in compound solids which cause the geometries to go missing when viewed in certain IFC viewer softwares (such as Solibri and Revit) due to the rendering rules of those softwares. Defaulted this now to export using the snapper's mesh instead to improve the consistency of the visibility of IFC symbol geometries in IFC viewer softwares. However, if a manufacturer wishes to still export their snapper using the sym based representation (possibly to export as a solid), they can override extend public bool useSymBasedRepresentations() method in IfcExportCoreObjectFactory to return true.

Handling import of IfcMappedRepresentation

Previously IFC import did not account for the mapping target of an IfcMappedRepresentation (only the mapping source's mapping origin) when calculating the IFC snapper's transform which resulted in multiple snappers being placed in the same location on import. Updated this so now the mapping target transform is applied onto the mapping source's mapping origin's transform on import to determine its position relative to the IFC project.

IFC export includes user drawn multifloors

Improved IFC export to include mezzanines, and user placed floors when the "Include architectural objects on exporting" setting is enabled.