Also hide Memcopy H to D and add setRecvFsPost27 to new stream

apps/gpu/LBM/MusselOyster/MusselOyster.cpp

src/gpu/VirtualFluids_GPU/Calculation/UpdateGrid27.cpp

src/gpu/VirtualFluids_GPU/Communication/ExchangeData27.cpp

src/gpu/VirtualFluids_GPU/GPU/CudaMemoryManager.cpp

src/gpu/VirtualFluids_GPU/GPU/CudaMemoryManager.h

src/gpu/VirtualFluids_GPU/GPU/GPU_Interface.h

src/gpu/VirtualFluids_GPU/GPU/LBMKernel.cu