Add support for IFC4 import/export with textures. Add support for entities IfcBlobTexture, IfcPixelTexture, IfcImageTexture. At least entity IfcIndexedColourMap is already implemented as it shows correctly. Attaching examples with textures from buildingSMART IFC.
This support is much needed because formally there is requirements to deliver data also in IFC format and now exporting reality meshes or terrain the texture material is lost.