Problem 693

There is small energy-momentum non-conservation which in some cases may provide
wrong distributions for thin and light target experiments. The problem is
created at G4HadronicInteraction class at PostStepDoIt when all final particles
are rotated on random angle. Pramary scatted particle is not rotated, so the
balance is broken - our HARP collegues observing cases when both scattered and
recoiled particles have the same phi angle instead of opposite.

Other minor problem: in the G4ElasticHadrNucleusHE the mass of a recoil nucleus
is roughly estimated , not taken from G4ParticleDefinition.