ENH: ITKv5_CONST macro for VerifyPreconditions() and VerifyInputInformation()

ITKv5_CONST enables backwards compatible behavior when ITKV4_COMPATIBILITY
is turned ON for methods which have acquired 'const' qualifier in ITKv5.
Breaking changes were originally introduced by ITK  commits
3e6b6f5bd6772316aa0fa6b89f31b42bef562112 (on 2018-10-18) and
16eae15c1bb6cc1bae9fba3e09a3102bdc02e955 (on 2018-10-23).

Author: hjmjohnson

include/itkDICOMOrientImageFilter.h

@@ -168,7 +168,7 @@ class ITK_TEMPLATE_EXPORT DICOMOrientImageFilter : public ImageToImageFilter<TIn
   SetInputCoordinateOrientation(OrientationEnum newCode);
 
   void
-  VerifyPreconditions() ITKv5_CONST override;
+  VerifyPreconditions() const override;
 
   /** Single-threaded version of GenerateData. This filter delegates
    * to PermuteAxesImageFilter and FlipImageFilter. */

include/itkDICOMOrientImageFilter.hxx

@@ -295,7 +295,7 @@ DICOMOrientImageFilter<TInputImage>::GenerateOutputInformation()
 
 template <typename TInputImage>
 void
-DICOMOrientImageFilter<TInputImage>::VerifyPreconditions() ITKv5_CONST
+DICOMOrientImageFilter<TInputImage>::VerifyPreconditions() const
 {
   Superclass::VerifyPreconditions();
 

include/itkNPasteImageFilter.h

@@ -170,11 +170,11 @@ class ITK_TEMPLATE_EXPORT NPasteImageFilter : public InPlaceImageFilter<TInputIm
    * \sa ProcessObject::VerifyInputInformation
    */
   void
-  VerifyInputInformation() ITKv5_CONST override
+  VerifyInputInformation() const override
   {}
 
   void
-  VerifyPreconditions() ITKv5_CONST override;
+  VerifyPreconditions() const override;
 
   bool
   CanRunInPlace() const override;

include/itkNPasteImageFilter.hxx

@@ -79,7 +79,7 @@ NPasteImageFilter<TInputImage, TSourceImage, TOutputImage>::GenerateInputRequest
 
 template <typename TInputImage, typename TSourceImage, typename TOutputImage>
 void
-NPasteImageFilter<TInputImage, TSourceImage, TOutputImage>::VerifyPreconditions() ITKv5_CONST
+NPasteImageFilter<TInputImage, TSourceImage, TOutputImage>::VerifyPreconditions() const
 {
   Superclass::VerifyPreconditions();