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/itkWaveletFrequencyInverse.h

@@ -175,7 +175,7 @@ class WaveletFrequencyInverse : public ImageToImageFilter<TInputImage, TOutputIm
   /** Input images do not occupy the same physical space.
    * Remove the check. */
   void
-  VerifyInputInformation() ITKv5_CONST override{};
+  VerifyInputInformation() const override{};
 
 private:
   unsigned int             m_Levels{ 1 };

include/itkWaveletFrequencyInverseUndecimated.h

@@ -167,7 +167,7 @@ class WaveletFrequencyInverseUndecimated : public ImageToImageFilter<TInputImage
   /** Input images do not occupy the same physical space.
    * Remove the check. */
   void
-  VerifyInputInformation() ITKv5_CONST override{};
+  VerifyInputInformation() const override{};
 
 private:
   unsigned int             m_Levels{ 1 };