Fix various msvc compiler warnings. With msvc the compiler flags are explicit passed to nvcc with -Xcompiler.

Renmade HOST in GridGenerator to CUDA_HOST because of a name conflict to MPI

Made VF_GPU work with the "new" cmake

implements a fix in the grid generator, that sets invalid STOPPER_UOT_OF_GRID_BOUNDARY nodes to INVALID_OUT_OF_GRID