Fix VTK memory leaks in SurfaceToImageFilter

... due to invalid vtkSmartPointer usage.

Signed-off-by: Taylor Braun-Jones <taylor.braun-jones@ge.com>
Fix memory leak in mitkImageVtkMapper2DLevelWindow unit test

Signed-off-by: Taylor Braun-Jones <taylor.braun-jones@ge.com>
Fix memory leaks in VtkPropRenderer::Initialize2DvtkCamera

Signed-off-by: Taylor Braun-Jones <taylor.braun-jones@ge.com>
Merge branch 'bug-16674-fix-memory-leaks-SurfaceToImageFilter'
Merge branch 'bug-16674-fix-memory-leaks-VtkPropRenderer'
Merge branch 'bug-16674-fix-memory-leaks-ImageVtkMapper2DLevelWindowTest'