COMP: Added missing header <functional> in itkAnchorCloseImageFilter.h

Fixes VC11 complaint about undefined std::greater in
itkAnchorCloseImageFilter.h

Change-Id: Iba0fb1125386cd59c96ca934391408c8c03d45e5
Merge branch 'itkAnchorCloseImageFilter_VC11_Comp_Fix_release' into release