ENH: support for VectorImage output to GradientRecursiveGaussian

Add support for VectorImage in the NthElementPixelAccessor by using
partial template specialization.

The implementation of the transformation of from local vector ro
physical vector has been extrated into overloaded member functions for
different image and pixel types.

Additionally, dead code was removed for the partially implemented
itk::Image of VariableLengthVectors.

Change-Id: I53ebbac83ede53f068a3c4e0189c8042845d89ae
Merge topic 'GradientRecursiveGaussianForVectorImages'

d4f4215 ENH: support for VectorImage output to GradientRecursiveGaussian
ENH: Improve MRCImageIO support for VectorImages

The handling of the ImageIO's interpretation of NumberOfComponents,
and PixelType has been improved to handle VectorImages. Specifically,
this will allow writing VectorImage from SimpleITK to be interpreted
as RGB images.

Additionally, the sample tilt mrc image has been added from the
original IJ paper, this includes advance information in the
header. This it further tested to improve coverage.

Change-Id: I2155610f870d83c5fcb9064476adedc355d69704
BUG: Correcting wrapping CMakeList.txt for DCMTK

The wrapping CMakeLists.txt file appears to be for prior
versions. This has been udpated to work with the current wrapping.

Change-Id: I3c978ac593c47faf5ac2ff3793fd21d2240da7e0
Merge topic 'FixDCMTKWrapITK'

db6456b BUG: Correcting wrapping CMakeList.txt for DCMTK
Merge topic 'MRCImageIOImprovements'

113bdf3 ENH: Improve MRCImageIO support for VectorImages
DOC: Modify AnisotropicDiffusionFunction comments.

Author: marktsuchida@gmail.com
Correct typos.

Change-Id: I3904ef11a2d70cfc11a92069bae37ebfff6ab1b3
Merge topic 'EditDoxygen_AnisotropicDiffusionFunction_1353438854'

97ac9d4 DOC: Modify AnisotropicDiffusionFunction comments.
COMP: Adding Valgrind suppression for NRRD IO on RH6

Change-Id: Idf5e07b038aac2e596046e2640375ffc8f5ce79b
ENH: Convert the Modulus filter to standard binary filter

By converting to a BinaryFunctor filter the ModulusImageFilter can
take a constant for either the first argument or the second thanks to
the generalization for the BinaryFunctor. And the additional
functionality of being able to operate on two images is also gained.

Change-Id: Ic0b796babcc4be6bbc3a989661383a4ec98f94cc
BUG: MetaImage data file was missing path.

When writing ROIs the filename of the data was missing the path that
should make it be stored in the same directory as the header file.

Also unified the hard-coded size of buffers used to store path names.
They are now using a common MAXPATHLENGHT defined symbol set to 2048.

Change-Id: I04a66defca593824b5c9c6bcd1e4a170f0553ad4
Merge branch 'MetaImagePathLengthBackport' into release-3.20
Merge branch 'release-3.20' into release
Merge branch 'release'
Merge topic 'NrrdIOValgrindSuppression'

0fc1730 COMP: Adding Valgrind suppression for NRRD IO on RH6
Merge topic 'ModulusToBinaryFunctor'

46dd44b ENH: Convert the Modulus filter to standard binary filter
ENH: Multiple metrics in registration methods.

This patch is the initial work necessary to integrate
multiple metrics in ITK.  This should allow
the user to place multiple image pairs into the method
with different metrics to perform
multi-image registration.  All the changes should be
backwards compatible.

Change-Id: I19f79627938883d49162422f315d40f63d18a142
ENH: Add MultiTransformBase

New base class for CompositeTransform and forthcoming
PolyAffine and Longitudinal transforms.

Change-Id: I052bfaf9ca880f83e9e28c75376dfea49390df7f
Merge topic 'MultiImageRegMethod'

03eccba ENH: Multiple metrics in registration methods.
BUG: unset environmental default number of threads

When ITK_GLOBAL_DEFAULT_NUMBER_OF_THREADS is set for testing a couple
of the MultiThreadEnv tests fail. A new feature is added to the
itkTestDriver to unset environmental variables.

Additionally, some itkTestDriver arguments are now correctly checking
that there were enough command line arguments left.

Change-Id: I270fe2f3d82c05ce5b30273ebd086782de98babb