BUG: Cppcheck ants final patch

Bugs are fixed int three files:

ImageRegistration/itkANTSImageRegistrationOptimizer.cxx
ImageRegistration/itkAvantsMutualInformationRegistrationFunction.h
Utilities/antsCommandLineParser.cxx

100% of tests are passed and changes can be merged to the main repository safely.

Note that you do not need to squash different commits. I have built each patch at the top of the previous one; therefore, this last patch contains all final changes.