Map background

I've added the background minimap from [here](http://dota2.gamepedia.com/File:Minimap_6.82.png).

Problem is that the minimap is not entirely accurate,as can be expected. Here's the issue:
Deaths around the fountain are to be expected around the paths and particularly the stairs because the movement is restricted there. When deaths are fitted to the stairs, other deaths occur in the woods, and visa versa:

![screenshot from 2014-12-18 00 32 48](https://cloud.githubusercontent.com/assets/1196596/5481177/f9f99684-864d-11e4-87ef-b018f6a16474.png)

I'm going for the fountain accuracy rather than the top-left and bottom-right accuracy. Ready for review, @AlexKolpa!