grid displayed regarding a relative position from the center grid; the filename gives the position; read and write methods updated
grid vector ok
Revert "grid vector ok"

This reverts commit 50cd68cebb212d56978b7180640db1b4c7b8e955.
grid vector ok
add the possibility to display several grids with the grid vector
save grid files OK, name based on their NESW position
corrected uint bug with grid positions
grid files saved when player changes the grid on which he is
added grid files loading from current player's grid north and east position
dynamic grid files loading and saving ! Only 3 grids loaded for tests, go north or south
Merge branch 'save_files' into terrain_renderer