Alter camera interactions to fix orbiting behaviour on rotate.
Alter camera interactions to fix orbiting behaviour on rotate.

Move the calculations for panning to a funcion to save computation.

Change-Id: I26934c7b2b1274ee3801758e45eeb67fb03fe107

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