Update copyright note of GUI

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>
Add missing variable conexp-namespaces for c.c.doc

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>
Fixed missing import of def-

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>