Update 0.2.1: Shadow changes

This small update brings some significant changes to how shadows are drawn. 

Shadows are now not fully opaque, and enemies disappear around corners and behind walls. Also, shadows are subsampled and have some static effect as well. Still playing around with it, but its a major design change and I'm really liking it. There might have been other changes here, but I don't remember them past the 4 hours I spent on shadows.