Add data file loading
Modify Map to send out-of-bounds cells to the opposite side of the map.

Mod: Change all array references to be [y][x], instead of [x][y].
Mod: Change get_cell() to correct coordinates for out-of-bounds requests.
	Ex: get_cell(7, 3) when the maximum X value is 5 would return the
	cell at (1, 3) instead. Note that coordinates start at (0, 0).