Improving data transfers between the GPU and the CPU.

src/core/tnlCuda.h

src/implementation/core/CMakeLists.txt

src/implementation/core/memory-operations.h

src/implementation/core/memory-operations_impl.cu

src/implementation/core/tnlCuda_impl.h

tests/unit-tests/core/cuda/tnlCudaMemoryOperationsTester.h