Removed obsolete methods from Simulation class hierarchy

Core/Simulation/GISASSimulation.cpp

Core/Simulation/GISASSimulation.h

Core/Simulation/OffSpecSimulation.cpp

Core/Simulation/OffSpecSimulation.h

Core/Simulation/Simulation.cpp

Core/Simulation/Simulation.h

Core/Simulation/SpecularSimulation.cpp

Core/Simulation/SpecularSimulation.h