COMP: ImageViewer depends on ITK.
COMP: Fixes warnings on signed/unsigned in TubeGraphSimilarity
Merge pull request #184 from aylward/ImageViewerDependsOnITK

COMP: ImageViewer depends on ITK.
COMP: Bump versions of CTK and VTK to match Slicer
Merge pull request #185 from aylward/BumpCTKVTK

COMP: Bump versions of CTK and VTK to match Slicer
Merge pull request #186 from aylward/TubeGraphSimilarityKernelMatrixWarnings

COMP: Fixes warnings on signed/unsigned in TubeGraphSimilarity
BUG: USE_SLICER (not BUILD_SLICER_EXT) flags if Slicer provides ITK, etc.
Merge pull request #187 from aylward/ITKv4WhenTubeTK_USE_SLICER

BUG: USE_SLICER (not BUILD_SLICER_EXT) flags if Slicer provides ITK, etc...