Added angleDiff() function to vector to get the difference in angle from one vector to another.

src/Vector.java

@@ -1,3 +1,4 @@
+import static java.lang.Math.acos;
 import static java.lang.Math.sqrt;
 
 public class Vector {
@@ -65,4 +66,9 @@ public class Vector {
         float mag = this.mag();
         return new Vector(x / mag, y / mag, z / mag);
     }
+
+    float angleDiff(Vector other){
+        float dot = this.dot(other);
+        return (float)acos(dot / (this.mag() * other.mag()));
+    }
 }