[fix] World preview at top/left of the map

[swed]

Hello,

Actually, you can't see the 'world preview' of all objects that are completely at top or left of the map.
For example, build something at the first tile on the left (or top), then look at it with the 'A' key :
The world preview isn't here.

That affects all previews (in info windows, monthly messages, ...).

So, Here is the patch I use to correct this bug (2 lines modified).

(bug screenshot : http://imagebin.ca/view/wEhpLzN.html).

(sorry for my english)
See ya,
Marc.

[prissi]

Thank you