ADD: add ParameterKey class + test

Code/Core/otbParameterKey.cxx

Code/Core/otbParameterKey.h

Code/Core/otbWrapperOutputImageParameter.h

Code/Wrappers/SWIG/itkBase.i

Testing/Core/CMakeLists.txt

Testing/Core/otbParameterKeyTest.cxx

Testing/Core/otbWrapperCoreTests.cxx