Add spaces around assignment operators
Add spaces around assignment operators

As the code style declares.

Contributes to issue CURA-1911.

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