Update 0.33

Switched trees to point clouds and added auto-generated colliders for them and large stones. No player collision yet, just missiles. And the shading is still off, the foliage had a translucent effect which is missing right now. I guess I'm going to fix that next and switch wyverns and caterpillars to point cloud models as well.

• Added various (and mod-able) brush images for point clouds.

• Trees use point cloud models now.

• Added auto-generated colliders for point clouds (used for tree foliage and large stones).

• Menhirs (large standing stones) now block missiles.

• Point cloud objects now fade out before wrapping to the other side of the world.

• Some performance optimizations for shadows.