Commit so i can pull.
Merge branch 'master' of https://github.com/schiem/roguelike
Merge branch 'master' of https://github.com/schiem/roguelike
Created a top layer, so we no longer have to worry about things overwriting
the terrain.  We can just place anything (enemies, items, whatever) into the
top_layer in the canvas, and it will get written overtop the terrain.
Still getting random seg_faults in the overworld.  Dungeons seem stable.