Created deprecated GLMappers module.

Everything related to OpenGL in MitkCore was moved a new module GLMappers, which has been marked deprecated. OpenGL related code in vtkPropRenderer has been commented out. The Modules (AlgorithmExt, DataTypesExt, MapperExt, ContourModel and PlanarFigures) have a dependency to GLMappers.
create new vtk based PlaneGeometryMapper
Renamed GLMappers to LegacyGL. Added first version of SurfaceVtkMapper2D.
Cleaning up code.
Format commit.
First version of the normal property.
Cleaning up and docu.
Renamed test of the mapper. Fixed normals opacity.
Minor cosmetic fixes.
Cleaning up in PropRenderer.
Format commit.
fix crosshair gap sizes and add property
add thick slice mode helperlines
fixed export macros
fixed order of modules in cmake
using vtktextActor to render textoverlay
using mitkOverlay to render annotations of PlanarFigures
vtkMitkRectangleProp now uses VTK to render.
finished drawing annotations with TextOverlays instead of WrtieSimpleText
using TextOverlay instead of WriteSimpleText