start normal calculation

fractional/src/geometry.rs

@@ -30,8 +30,9 @@ use crate::vector::Vector;
 #[derive(Debug)]
 pub struct Polyeder<T>
 where T: Add + Sub + Neg + Mul + Div + Debug + Copy + Trig {
-    points :Vec<Vector<T>>,
-    faces  :Vec<Vec<usize>>,
+    points  :Vec<Vector<T>>,
+    faces   :Vec<Vec<usize>>,
+    normals :Vec<Vector<T>>,
 }
 
 pub trait Primitives<T>