ENH: Do not produce error if input is empty. Replaced error macro with debug macro
ENH: Do not produce error if input is empty. Replaced error macro with debug macro

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