COMP: Make Doxygen Modules group definition consistent.

Make ITK module group definition in CMake/ITKModuleDoxygen.cmake
consistent with CMake/ITKGroups.cmake.

Change-Id: Ib956a46e2f8cd33ac095608e8b2d8f1577d76355
DOC: ThresholdBetween does not exist, it should be ThresholdOutside

Change-Id: If1854bd55e7b7f78e6626d359fe97888db91b1a7
BUG: GDCM does not apply rescale slope / intercept on write.

Make use of the InternalComponentType, which is the pixel type
before rescale slope/intercept have been applied when reading from disk.

This internal component and rescale slope from the reader can be used in
a writer for the DICOM image with

  dicomWriter->SetImageIO( readersGDCMImageIO );
  dicomWriter->UseInputMetaDataDictionaryOff();

Make sure the written DICOM images are verified against baselines in the
tests.

Change-Id: I1cecec83d2bfeac5a8e64b77062a46dcd49746f7
Merge topic 'DocThresholdImageFilter'

bd7aaecb DOC: ThresholdBetween does not exist, it should be ThresholdOutside
Merge topic 'DoxGroupDef'

670ba700 COMP: Make Doxygen Modules group definition consistent.
Merge topic 'RescaleSlopeIntercept'

847ec2b7 BUG: GDCM does not apply rescale slope / intercept on write.