Refactoring in fitting to get nicer python interface

App/src/TestFormFactors.cpp

App/src/TestFourier.cpp

App/src/TestIsGISAXS1.cpp

App/src/TestIsGISAXS10.cpp

App/src/TestIsGISAXS11.cpp

App/src/TestIsGISAXS12.cpp

App/src/TestIsGISAXS14.cpp

App/src/TestIsGISAXS15.cpp

App/src/TestIsGISAXS2.cpp

App/src/TestIsGISAXS3.cpp

App/src/TestIsGISAXS4.cpp

App/src/TestIsGISAXS5.cpp

App/src/TestIsGISAXS6.cpp

App/src/TestIsGISAXS7.cpp

App/src/TestIsGISAXS8.cpp

App/src/TestIsGISAXS9.cpp

App/src/TestMesoCrystal2.cpp

App/src/TestMiscellaneous.cpp

App/src/TestPolarizedDWBAZeroMag.cpp

Core/PythonAPI/src/FormFactorBox.pypp.cpp