Added progress updates when reading a volume
Added progress updates when reading a volume

Updating progress per page seems to give reasonable updates.

Change-Id: I142f5e18fad8294df2367d82bea171567c005fa5

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