BUG: If USE_SLICER then no need to declare dependency on ITK
STYLE: Replace test of size()==0 with calls to empty
Merge pull request #188 from aylward/ITKv4WhenTubeTK_USE_SLICER

BUG: If USE_SLICER then no need to declare dependency on ITK
Merge pull request #189 from aylward/UseEmptyInSynRecordManager

STYLE: Replace test of size()==0 with calls to empty