Add world representation as hittable list

rtweekend.hpp

@@ -0,0 +1,19 @@
+#ifndef RTWEEKEND_H
+#define RTWEEKEND_H
+
+#include <math.h>
+#include <memory>
+
+/* Utility functions */
+double degrees_to_radians(double d)
+{
+    return d * M_PI / 180;
+}
+
+/* Common internal headers */
+
+#include "ray.hpp"
+#include "vec3.hpp"
+
+
+#endif