BUG: Fix runtime bug with ITK_FUTURE_LEGACY_REMOVE

When ITK_FUTURE_LEGACY_REMOVE is used inconsistently in ITK and BRAINSTools
it causes very difficult to diagnose virtual function failures.  This patch
set fixes the problem by pushing the use of ITK_FUTURE_LEGACY_REMOVE into
ITKv4 so that it is mandated to be consistently used.