[VTK-5069] Distinguish between fields and select in searcher
[VTK-5069] Distinguish between fields and select in searcher

Fields include a list of properties and additional special names, such
as 'uri', 'type' and 'acl'

vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk,vtkio/vtk