
ENH: Make a couple methods virtual.

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