BUG: Fixed a bug in gtractResampleDWIInPlace

In image origin conversion, GetTranslation() is replaced by GetOffset().
ENH: Add a test for gtractResampleDWIInPlace

To create a test:
- I chose a sample DWI image and its corresponding T2 image.
- Extracted the b0 image of the DWI file using extractNrrdVectorIndex.
- Used BRAINSFit to a run a rigid registration between b0 image and T2
image.
- Ran gtractResampleDWIInPlace to align the input DWI image using the
rigid transform.

I did following to verify the ouput of the gtractResampleDWIInPlace
after
fixing its bug:
- I used ResampleInPlace as the interpolation option in BRAINSFit to
obtain warped b0 image.
- In Slicer, I compared the above warped b0 image by BRAINSFit with the
b0 component of the aligned DWI image by gtractResampleDWIInPlace to
make sure they completely overlaps.