Optimize polygon rasterization

[JD557]

Adds some optimizations to the polygon rasterization.

• Marks some stuff as lazy val (e.g. using the known face, one can do some preculling before computing the aabb, and vice versa), - Avoids the use of distinct (which allocates a HashSet)
• Short-circuits faceAt and contains
• Picks a better point for the knownFace test (the center sometimes was outside of the polygon... I ntoiced the same issue with the centroid, which is probably due to integer math)
• Adds an AABB builder, to avoid iterating over the points multiple times.

This optimizations led to a ~2x performance improvement when rendering the Stanford bunny. After this, I mostly just see Iterator.next() on the hot spot list.