Adding new base class for all VTK Mapper

Refactoring the Mapper class architecture by introducing a new class for
all existing VTK Mappers. The designated child classes must still be
adjusted in order to inherit from this class.
Adding base class for all GLMappers

This class will be parent class for all current GLMappers
introduce typedefs to map old classes to new classes

replace old mapper base classes in mitkVtkPropRenderer and
vtkMitkRenderProp by new GL/VTKMapper
Unify comment style in Mapper.h and add comments
Deleted old cpp base class files
Adding comments in order to obtain a more detailed documentation
Porting all GLMapper2D to new base class GLMapper
Port existing VTK mappers to one base class
Replace GenerateData() by GenerateDataForRenderer()
Merge GenerateData() with GenerateDataForRenderer()
Merge GenerateData() with GenerateDataForRenderer()
Merge GenerateData() with GenerateDataForRenderer()
Include GenerateData() into GenerateDataForRenderer()
Insert GenerateData() into GenerateDataForRenderer()
Paste GenerateData() into GenerateDataForRenderer()
Paste GenerateData() into GenerateDataForRenderer()
Paste GenerateData() into GenerateDataForRenderer()
Paste GenerateData() into GenerateDataForRenderer()
Paste GenerateData() into GenerateDataForRenderer()
Adding new files and removing deleting files to files.cmake