Guard point representations so SetGet will not segfault.
Guard point representations so SetGet will not segfault.

Change-Id: I86ee5abdc67e200558805af65b7fda9894d1241c

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