Revert "lil fix: don't compute overhang on first layer"
Revert "lil fix: don't compute overhang on first layer"

This reverts commit bec51eb0bda998320db412001606de482957085e.

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