DOC: Explain ordering of eigenvectors.
DOC: Explain ordering of eigenvectors.

Change-Id: I5c76b39552eca8bdd1ede67a5ff55004da9385ce

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