grid_reader_cursor_right
void grid_reader_cursor_right(struct grid_reader *, int, int, int);
grid_reader_cursor_right(&gr, 1, all, onemore);
grid_reader_cursor_right(&gr, 1, 0, onemore);
grid_reader_cursor_right(&gr, 0, 0, 0);
grid_reader_cursor_right(&gr, 0, 0, 0);