Correctly draw the white rectangle in the world map window

[axx0]

When at the bottom of the screen, the rectangle should be positioned slightly more down (it's drawn correctly for the northern part I think).

[Solen1985]

The square is incorrectly sized in the actual game as well... I will consider this a bug in the original game and fix it. While I'm fixing this, I will also adjust the white square to reflect the screen size, with the expanded window feature that I'm working on.

[axx0]

Yes I've also noticed it's broken in the original. Especially the positioning of the rectangle when you're moving with the mouse at the bottom of the map.

[Solen1985]

Moved back to alpha.2.