ENH: Added compatability for projects using VTK_SOURCE_DIR, TCL_LIBRARY, and TK_LIBRARY from VTK's cache.  These settings should not be used by new projects.
ENH: Added compatability for projects using VTK_SOURCE_DIR, TCL_LIBRARY, and TK_LIBRARY from VTK's cache.  These settings should not be used by new projects.

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