Added masked iterator for OutputData and used these for multithreading

Core/Algorithms/inc/DWBASimulation.h

Core/Algorithms/inc/Experiment.h

Core/Algorithms/inc/LayerDWBASimulation.h

Core/Algorithms/inc/MultiLayerDWBASimulation.h

Core/Algorithms/inc/ThreadInfo.h

Core/Algorithms/src/DWBASimulation.cpp

Core/Algorithms/src/DiffuseDWBASimulation.cpp

Core/Algorithms/src/Experiment.cpp

Core/Algorithms/src/GISASExperiment.cpp

Core/Algorithms/src/LayerDWBASimulation.cpp

Core/Algorithms/src/LayerDecoratorDWBASimulation.cpp

Core/Algorithms/src/MultiLayerDWBASimulation.cpp

Core/Algorithms/src/MultiLayerRoughnessDWBASimulation.cpp

Core/Core.pro

Core/Tools/inc/MaskedOutputDataIterator.h

Core/Tools/inc/OutputDataIterator.h

Core/Tools/inc/OutputDataMaskStrategies.h