implements infrastructre for flux BCs

src/GksGpu/BoundaryConditions/BoundaryCondition.cpp

src/GksGpu/BoundaryConditions/BoundaryCondition.h

src/GksGpu/BoundaryConditions/InflowComplete.cu

src/GksGpu/BoundaryConditions/InflowComplete.h

src/GksGpu/BoundaryConditions/Open.cu

src/GksGpu/CellProperties/CellProperties.cuh

src/GksGpu/DataBase/DataBaseAllocatorCPU.cpp

src/GksGpu/DataBase/DataBaseAllocatorGPU.cpp

src/GksGpu/FluxComputation/FluxComputation.cu

src/GksMeshAdapter/MeshCell.cpp

src/GksMeshAdapter/MeshCell.h

targets/apps/GKS/Flame7cm/Flame7cm.cpp