Making grid_gpu CUDA compilable

src/Grid/Encap.hpp

src/Grid/grid_base_impl_layout.hpp

src/Grid/grid_base_implementation.hpp

src/Grid/grid_gpu.hpp

src/Grid/grid_sm.hpp

src/Grid/grid_unit_tests.hpp

src/Grid/util.hpp

src/Makefile.am

src/Point_test.hpp

src/Space/Shape/Point.hpp

src/Space/Shape/Sphere.hpp

src/Vector/map_vector.hpp

src/main.cpp

src/memory_ly/memory_array.hpp

src/memory_ly/memory_c.hpp

src/memory_ly/memory_conf.hpp

src/memory_ly/t_to_memory_c.hpp

src/util/boost_multi_array_openfpm.hpp

src/util/compute_optimal_device_grid.hpp

src/util/ct_array.hpp