ENH: Store string dimensions in the image data.
ENH: Store string dimensions in the image data.

Use the origin and spacing (not used here for anything else) to store
the dimensions of the rendered string. Especially useful when the image
is scaled to the next power of two.

Change-Id: I9bb1dd05c3c55899aeb8e7d51947f777ea170eb8

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