Add IsExplicit to conversion operators for C++11 support.
Add IsExplicit to conversion operators for C++11 support.

Change-Id: I3a4d09b345d093b41a915dedd4798283d8b316f1

sankhesh/VTK,candy7393/VTK,sumedhasingla/VTK,msmolens/VTK,msmolens/VTK,keithroe/vtkoptix,gram526/VTK,sumedhasingla/VTK,berendkleinhaneveld/VTK,hendradarwin/VTK,johnkit/vtk-dev,demarle/VTK,demarle/VTK,berendkleinhaneveld/VTK,mspark93/VTK,msmolens/VTK,gram526/VTK,sumedhasingla/VTK,sankhesh/VTK,msmolens/VTK,SimVascular/VTK,sumedhasingla/VTK,msmolens/VTK,hendradarwin/VTK,berendkleinhaneveld/VTK,sumedhasingla/VTK,ashray/VTK-EVM,gram526/VTK,keithroe/vtkoptix,jmerkow/VTK,sumedhasingla/VTK,gram526/VTK,ashray/VTK-EVM,berendkleinhaneveld/VTK,sankhesh/VTK,sankhesh/VTK,mspark93/VTK,ashray/VTK-EVM,jmerkow/VTK,SimVascular/VTK,msmolens/VTK,demarle/VTK,johnkit/vtk-dev,demarle/VTK,demarle/VTK,keithroe/vtkoptix,ashray/VTK-EVM,candy7393/VTK,berendkleinhaneveld/VTK,sumedhasingla/VTK,SimVascular/VTK,candy7393/VTK,hendradarwin/VTK,demarle/VTK,candy7393/VTK,candy7393/VTK,berendkleinhaneveld/VTK,demarle/VTK,candy7393/VTK,ashray/VTK-EVM,keithroe/vtkoptix,SimVascular/VTK,SimVascular/VTK,sumedhasingla/VTK,johnkit/vtk-dev,ashray/VTK-EVM,keithroe/vtkoptix,SimVascular/VTK,hendradarwin/VTK,msmolens/VTK,msmolens/VTK,mspark93/VTK,jmerkow/VTK,johnkit/vtk-dev,jmerkow/VTK,jmerkow/VTK,berendkleinhaneveld/VTK,hendradarwin/VTK,SimVascular/VTK,keithroe/vtkoptix,candy7393/VTK,candy7393/VTK,johnkit/vtk-dev,mspark93/VTK,mspark93/VTK,demarle/VTK,jmerkow/VTK,mspark93/VTK,keithroe/vtkoptix,gram526/VTK,mspark93/VTK,sankhesh/VTK,johnkit/vtk-dev,gram526/VTK,keithroe/vtkoptix,sankhesh/VTK,mspark93/VTK,hendradarwin/VTK,johnkit/vtk-dev,hendradarwin/VTK,gram526/VTK,sankhesh/VTK,jmerkow/VTK,SimVascular/VTK,gram526/VTK,sankhesh/VTK,ashray/VTK-EVM,ashray/VTK-EVM,jmerkow/VTK