Add 0-sized arrays for particles that will be created

doc/RTD/source/Snapshots/index.rst

examples/main.c

examples/main_fof.c

src/common_io.h

src/common_io_cells.c

src/distributed_io.c

src/line_of_sight.c

src/parallel_io.c

src/parallel_io.h

src/serial_io.c

src/serial_io.h

src/single_io.c

src/single_io.h

src/space.c

src/space.h