ISimulation: cache result. Some unit tests broken

Device/Histo/SimulationResult.cpp

Device/Histo/SimulationResult.h

Sim/Simulation/DepthProbeSimulation.cpp

Sim/Simulation/DepthProbeSimulation.h

Sim/Simulation/ISimulation.cpp

Sim/Simulation/ISimulation.h

Sim/Simulation/OffSpecularSimulation.cpp

Sim/Simulation/OffSpecularSimulation.h

Sim/Simulation/ScatteringSimulation.cpp

Sim/Simulation/ScatteringSimulation.h

Sim/Simulation/SpecularSimulation.cpp

Sim/Simulation/SpecularSimulation.h

auto/Wrap/doxygenDevice.i

auto/Wrap/doxygenSim.i

auto/Wrap/libBornAgainDevice.py

auto/Wrap/libBornAgainDevice_wrap.cpp

auto/Wrap/libBornAgainSim.py

auto/Wrap/libBornAgainSim_wrap.cpp