Fix leaks found by running non-rendering unit tests with VTK_DEBUG_LEAKS

Summary of tests that failed when built against a VTK library with VTK_DEBUG_LEAKS enabled:

mitkSliceNavigationControllerTest -- FIXED in Core/Code/DataManagement/mitkBaseGeometry.cpp
vtkMitkThickSlicesFilterTest -- FIXED in Core/Code/Testing/vtkMitkThickSlicesFilterTest.cpp
mitkClippedSurfaceBoundsCalculatorTest -- FIXED in Core/Code/Testing/mitkClippedSurfaceBoundsCalculatorTest.cpp
mitkAffineTransformBaseTest -- FIXED in Core/Code/Testing/mitkAffineTransformBaseTest.cpp
mitkLookupTableTest -- FIXED in Core/Code/Testing/mitkLookupTableTest.cpp
mitkBaseGeometryTest -- FIXED in Core/Code/Testing/mitkBaseGeometryTest.cpp
mitkTrackingVolumeGeneratorTest -- FIXED in Modules/IGT/TrackingDevices/mitkTrackingVolumeGenerator.cpp

Signed-off-by: Taylor Braun-Jones <taylor.braun-jones@ge.com>