map validation about so_long HOT 1 CLOSED

1. Open map file by "open"
   -> if return value of O_DIRECTORY > 0 : directory
   -> if return value of O_RDONLY < 0 : unavailable
2. Get number of lines of map file by "get_num_line(path)"
3. malloc char **
4. while get_next_line
5. check rectangular
6. check closed by walls
7. check E, P, C
8. check valid path

from so_long.