rtiow: add blox with gloxy edges.

Fixed bug in kdtree that this uncovered.
Marked Hit and it's dependencies as needing to implement the Debug
trait.

rtiow/renderer/src/sphere.rs

@@ -8,6 +8,7 @@ use crate::{
     vec3::{dot, Vec3},
 };
 
+#[derive(Debug)]
 pub struct Sphere<M>
 where
     M: Material,