COMP: ThreadJob NULL not defined.

ITK/Modules/Core/Common/include/itkThreadJob.h:46:16: error: 'NULL' was not
declared in this scope

Change-Id: If08e2fe5dcee0c28408a9d783649f83134985ae8
COMP: Remove unused typedefs in LevelSetsv4Visualization.

Change-Id: Id7837dfbc159febef5b85d359f4a5f90cda3c1c3
COMP: Remove unused typedef's in VtkGlue.

Change-Id: Ic7e9a3a24a49a13a04932d6c806482a0516fae88
Merge topic 'LevelSetUnused'

d5940ddc COMP: Remove unused typedefs in LevelSetsv4Visualization.
Merge topic 'VtkGlueUnused'

d8e3ba3d COMP: Remove unused typedef's in VtkGlue.
Merge topic 'ThreadJob'

71c3e175 COMP: ThreadJob NULL not defined.