bugfix: commandSocket depends on there being a NoneType (CURA-581)
bugfix: commandSocket depends on there being a NoneType (CURA-581)

Ultimaker/CuraEngine,alephobjects/CuraEngine,totalretribution/CuraEngine,alephobjects/CuraEngine,Ultimaker/CuraEngine,alephobjects/CuraEngine,ROBO3D/CuraEngine,totalretribution/CuraEngine,ROBO3D/CuraEngine,totalretribution/CuraEngine,ROBO3D/CuraEngine