COMP: Updated ANTS to use tarball of BOOST as well.
COMP: Fix antsUtilities library linkage

When building BRAINSTools within DTIPrep antsUtilities
libraries were placed in the DTIPrep-build/lib directory
rather than the BRAINSTools-build/lib directory, so link
against the proper directory.
BUG: Regression from Dicom2Nrrd introduced

A DWI data set that was not represented in the DWI testing suite identified
a regression in the DWIConvert program introduced during refactoring.

This may be an issue with behavioral changes in DCMTK between stand-alone builds
and slicer builds, but that has not been confirmed.