start implementation of MultiGPU communication

CMakeLists.txt

src/GksGpu/Analyzer/EnstrophyAnalyzer.cu

src/GksGpu/Analyzer/EnstrophyAnalyzer.h

src/GksGpu/Analyzer/KineticEnergyAnalyzer.cu

src/GksGpu/Analyzer/KineticEnergyAnalyzer.h

src/GksGpu/Communication/Communicator.cpp

src/GksGpu/Communication/Communicator.cu

src/GksGpu/Communication/Communicator.h

src/GksGpu/Communication/package.include

src/GksGpu/DataBase/DataBaseAllocator.h

src/GksGpu/DataBase/DataBaseAllocatorCPU.cpp

src/GksGpu/DataBase/DataBaseAllocatorCPU.h

src/GksGpu/DataBase/DataBaseAllocatorGPU.cpp

src/GksGpu/DataBase/DataBaseAllocatorGPU.h

src/GksGpu/TimeStepping/NestedTimeStep.cpp

src/GksGpu/TimeStepping/NestedTimeStep.h

src/GksMeshAdapter/GksMeshAdapter.cpp

src/GksMeshAdapter/GksMeshAdapter.h

src/GridGenerator/grid/Grid.h

src/GridGenerator/grid/GridBuilder/MultipleGridBuilder.cpp