Implemented a custom map icon.

Rewritten as a map script with pre-defined land boundaries and randomized terrain, features, resources, lakes, and rivers.

The map is now updated to be closer to reality:
-Central desert is removed.
-Northern tundra is expanded.
-Southern tundra is removed.

Works now... I hope!

Map should now appear in map list. Not sure what the problem was.

Forgot to remove something...