renaming interpolation cell struct

src/gpu/VirtualFluids_GPU/Calculation/Cp.cpp

...U/DataStructureInitializer/GridReaderFiles/GridReader.cpp

...tructureInitializer/GridReaderGenerator/GridGenerator.cpp

...izer/GridReaderGenerator/IndexRearrangementForStreams.cpp

.../GridReaderGenerator/IndexRearrangementForStreamsTest.cpp

...tializer/GridReaderGenerator/InterpolationCellGrouper.cpp

...izer/GridReaderGenerator/InterpolationCellGrouperTest.cpp

src/gpu/VirtualFluids_GPU/FindInterface/FindInterface.cpp

src/gpu/VirtualFluids_GPU/GPU/CudaMemoryManager.cpp

src/gpu/VirtualFluids_GPU/GPU/LBMKernel.cu

...tualFluids_GPU/KernelManager/GridScalingKernelManager.cpp

...irtualFluids_GPU/KernelManager/GridScalingKernelManager.h

src/gpu/VirtualFluids_GPU/LBM/LB.h

src/gpu/VirtualFluids_GPU/Output/InterfaceDebugWriter.hpp

src/gpu/VirtualFluids_GPU/Output/OffsetWriter.hpp

src/gpu/VirtualFluids_GPU/Output/PosVecIntWriter.hpp

src/gpu/VirtualFluids_GPU/Output/interfaceWriter.hpp