JSON fix: made retraction_combing not editable per mesh any more (CURA-1134)
JSON fix: made retraction_combing not editable per mesh any more (CURA-1134)

Whether combing is no_skin now actually is retrieved globally

hmflash/Cura,Curahelper/Cura,hmflash/Cura,fieldOfView/Cura,Curahelper/Cura,ynotstartups/Wanhao,ynotstartups/Wanhao,fieldOfView/Cura