No Rotate on Line Sprites

[hallpell]

We allow changing the rotation style of Line Sprites to No Rotate, which really hobbles their usefulness. We should probably not allow this and throw an error if you try.

Based on observing the effects, I suspect we're implementing this with a Rectangle Sprite under the hood, and when you set No Rotate it makes x1 and y1 change the length of the Rectangle Sprite, but then we can't rotate it so it just hangs out.