adept to CSXCAD API changes & code cleanups

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
fix in deleting properties or primitives

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
always create a primitives editor layout

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>