Adding cliff sprites to accommodate biome transitions

[sashman]

Background

Once the terrain maps are able to output WATER background terrain tile types, the ciff sprites currently used will sit on top of the WATER tiles.

What needs to be done

*Possibly add a new type of cliffs that are thicker and accommodate the transition between water and grass. This will be an opportunity to make them look better, like having cliffs that meet with waves or cliffs that look a bit sandy.

How to do it

Make the new sprites.

Get the terrain generator to highlight whether this is a biome border cliff and make sure to render the appropriate sprite.