Add test `layers' to Makefile.
Add test `layers' to Makefile.

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