Merge branch 'feature/structuredgridwriter' into 'master'

dune.module

dune/vtk/datacollector.hh

dune/vtk/datacollectors/continuousdatacollector.hh

dune/vtk/datacollectors/discontinuousdatacollector.hh

dune/vtk/datacollectors/quadraticdatacollector.hh

dune/vtk/datacollectors/spdatacollector.hh

dune/vtk/datacollectors/structureddatacollector.hh

dune/vtk/datacollectors/yaspdatacollector.hh

dune/vtk/gridcreator.hh

dune/vtk/utility/string.hh

dune/vtk/vtkfunction.hh

dune/vtk/vtktypes.cc

dune/vtk/vtktypes.hh

dune/vtk/vtkwriter.hh

dune/vtk/writers/vtkimagedatawriter.hh

dune/vtk/writers/vtkimagedatawriter.impl.hh

dune/vtk/writers/vtkrectilineargridwriter.hh

dune/vtk/writers/vtkrectilineargridwriter.impl.hh

dune/vtk/writers/vtkstructuredgridwriter.hh

dune/vtk/writers/vtkstructuredgridwriter.impl.hh