vtkWeb: Add appropriate error codes for launch requests
vtkWeb: Add appropriate error codes for launch requests

Rather than returning 200 ( ok ) set the response code to an
appropriate error code.

Change-Id: I5a474cb0ffd66881216d1600b51a1f560f5b2207

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