Merge branch 'ff51' into 'develop'

Doc/FFCatalog/fig/ff2/bornplot.py

Examples/varia/CustomFormFactor.py

Sample/HardParticle/FormFactorBox.cpp

Sample/HardParticle/FormFactorBox.h

Sample/HardParticle/FormFactorCone.cpp

Sample/HardParticle/FormFactorCone.h

Sample/HardParticle/FormFactorCylinder.cpp

Sample/HardParticle/FormFactorCylinder.h

Sample/HardParticle/FormFactorEllipsoidalCylinder.cpp

Sample/HardParticle/FormFactorEllipsoidalCylinder.h

Sample/HardParticle/FormFactorFullSphere.cpp

Sample/HardParticle/FormFactorFullSphere.h

Sample/HardParticle/FormFactorFullSpheroid.cpp

Sample/HardParticle/FormFactorFullSpheroid.h

Sample/HardParticle/FormFactorHemiEllipsoid.cpp

Sample/HardParticle/FormFactorHemiEllipsoid.h

Sample/HardParticle/FormFactorHollowSphere.cpp

Sample/HardParticle/FormFactorHollowSphere.h

Sample/HardParticle/FormFactorLongBoxGauss.cpp

Sample/HardParticle/FormFactorLongBoxGauss.h