optimize exponents summation

Base/Math/Numeric.cpp

Base/Math/Numeric.h

Resample/Particle/ReMesocrystal.cpp

Resample/Particle/ReMesocrystal.h

Resample/Processed/Slicer.cpp

Sample/Particle/Mesocrystal.cpp

Sample/Particle/Mesocrystal.h

auto/Wrap/libBornAgainBase_wrap.cpp

auto/Wrap/libBornAgainDevice_wrap.cpp

auto/Wrap/libBornAgainFit_wrap.cpp

auto/Wrap/libBornAgainParam_wrap.cpp

auto/Wrap/libBornAgainResample_wrap.cpp

auto/Wrap/libBornAgainSample_wrap.cpp

auto/Wrap/libBornAgainSim_wrap.cpp