Summary of bug description
   * Actual behaviour: Binary images of type 'unsigned char' are not rendered in the 3D view
   * Expected behaviour: They should be shown as all other imagesd, too.
 
Cause of the bug
VTK interprets unsigned char images as RGBA color image even if they only have one component.
Their mapping through the lookup table for the 3D texture is controled vias the bool variable 'MapColorScalarsThroughLookupTable'.
If this bool is false, the binary image wrongly interpreted as color image does not have a lookup table and is not mapped.
The variable is set to false because color images are displayed as greyscale if not.

Proposed solution
In mitkGeometry2DDataVtkMapper3D, it is already known if an image is binary or not. So in case of binary images, set the variable 'MapColorScalarsThroughLookupTable' to true.

Affected classes
mitkGeometry2DDataVtkMapper3D.cpp

How will the bugfix get tested?
Manually by loading an arbitrary unsigned character binary image and looking if it is displayed in the 3D view.