Tile edge detection for a smooth environment.

I found a great new artist for the Gnome Mountain project, and with that came new tiles for my environment, which meant I needed to add edge detection to make a smooth and better looking world.

Here is what the new Gnome Mountain is looking like with edge detection, new tiles and also new sprites: http://i52.tinypic.com/ny5t6w.png

For anybody that is curious, here is the code I use to detect edges: http://mage360.pastebin.com/6gEe3McP