enforce single slicing by commandSocket.
enforce single slicing by commandSocket.

ROBO3D/CuraEngine,Ultimaker/CuraEngine,alephobjects/CuraEngine,Ultimaker/CuraEngine,ROBO3D/CuraEngine,totalretribution/CuraEngine,totalretribution/CuraEngine,pratikshashroff/pcura,pratikshashroff/pcura,alephobjects/CuraEngine,totalretribution/CuraEngine,pratikshashroff/pcura,ROBO3D/CuraEngine,alephobjects/CuraEngine