Converts a cell coordinate to a sector coordinate.
See Property for a detailed description of the relationship between sectors and cells.
void convert_cell_to_sector (int cell_x, int cell_z)
{
printf ("cell (%d, %d) is in sector (%d, %d)\n", cell_x, cell_z,
aw_sector_from_cell (cell_x), aw_sector_from_cell (cell_z));
}