Added missing include after recent changes to the scene class.
Added missing include after recent changes to the scene class.

collects/VTK,candy7393/VTK,naucoin/VTKSlicerWidgets,johnkit/vtk-dev,ashray/VTK-EVM,SimVascular/VTK,SimVascular/VTK,ashray/VTK-EVM,SimVascular/VTK,naucoin/VTKSlicerWidgets,demarle/VTK,aashish24/VTK-old,arnaudgelas/VTK,cjh1/VTK,gram526/VTK,jmerkow/VTK,naucoin/VTKSlicerWidgets,mspark93/VTK,SimVascular/VTK,sumedhasingla/VTK,berendkleinhaneveld/VTK,keithroe/vtkoptix,keithroe/vtkoptix,keithroe/vtkoptix,msmolens/VTK,hendradarwin/VTK,mspark93/VTK,gram526/VTK,collects/VTK,jeffbaumes/jeffbaumes-vtk,candy7393/VTK,spthaolt/VTK,gram526/VTK,hendradarwin/VTK,naucoin/VTKSlicerWidgets,biddisco/VTK,spthaolt/VTK,mspark93/VTK,spthaolt/VTK,SimVascular/VTK,candy7393/VTK,cjh1/VTK,aashish24/VTK-old,aashish24/VTK-old,keithroe/vtkoptix,aashish24/VTK-old,candy7393/VTK,collects/VTK,biddisco/VTK,sumedhasingla/VTK,candy7393/VTK,cjh1/VTK,gram526/VTK,candy7393/VTK,johnkit/vtk-dev,demarle/VTK,hendradarwin/VTK,candy7393/VTK,daviddoria/PointGraphsPhase1,berendkleinhaneveld/VTK,arnaudgelas/VTK,mspark93/VTK,arnaudgelas/VTK,jmerkow/VTK,berendkleinhaneveld/VTK,sumedhasingla/VTK,jmerkow/VTK,gram526/VTK,sumedhasingla/VTK,msmolens/VTK,jmerkow/VTK,daviddoria/PointGraphsPhase1,jeffbaumes/jeffbaumes-vtk,sankhesh/VTK,msmolens/VTK,biddisco/VTK,sankhesh/VTK,sumedhasingla/VTK,mspark93/VTK,arnaudgelas/VTK,jeffbaumes/jeffbaumes-vtk,naucoin/VTKSlicerWidgets,ashray/VTK-EVM,SimVascular/VTK,arnaudgelas/VTK,jmerkow/VTK,cjh1/VTK,johnkit/vtk-dev,jmerkow/VTK,johnkit/vtk-dev,johnkit/vtk-dev,candy7393/VTK,johnkit/vtk-dev,daviddoria/PointGraphsPhase1,berendkleinhaneveld/VTK,jeffbaumes/jeffbaumes-vtk,msmolens/VTK,hendradarwin/VTK,SimVascular/VTK,keithroe/vtkoptix,cjh1/VTK,johnkit/vtk-dev,ashray/VTK-EVM,biddisco/VTK,aashish24/VTK-old,demarle/VTK,sumedhasingla/VTK,berendkleinhaneveld/VTK,msmolens/VTK,mspark93/VTK,gram526/VTK,gram526/VTK,collects/VTK,sankhesh/VTK,keithroe/vtkoptix,arnaudgelas/VTK,jeffbaumes/jeffbaumes-vtk,biddisco/VTK,msmolens/VTK,biddisco/VTK,gram526/VTK,collects/VTK,ashray/VTK-EVM,collects/VTK,sankhesh/VTK,hendradarwin/VTK,spthaolt/VTK,cjh1/VTK,spthaolt/VTK,SimVascular/VTK,berendkleinhaneveld/VTK,keithroe/vtkoptix,ashray/VTK-EVM,mspark93/VTK,ashray/VTK-EVM,jmerkow/VTK,biddisco/VTK,spthaolt/VTK,demarle/VTK,demarle/VTK,msmolens/VTK,msmolens/VTK,sumedhasingla/VTK,ashray/VTK-EVM,jmerkow/VTK,sankhesh/VTK,hendradarwin/VTK,daviddoria/PointGraphsPhase1,aashish24/VTK-old,naucoin/VTKSlicerWidgets,jeffbaumes/jeffbaumes-vtk,demarle/VTK,mspark93/VTK,berendkleinhaneveld/VTK,demarle/VTK,daviddoria/PointGraphsPhase1,keithroe/vtkoptix,sankhesh/VTK,sumedhasingla/VTK,hendradarwin/VTK,daviddoria/PointGraphsPhase1,sankhesh/VTK,demarle/VTK,sankhesh/VTK,spthaolt/VTK