ENH: use observers instead of Tk bindings
ENH: use observers instead of Tk bindings

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