Implement Circle header, rename all files to use .hpp extension.

include/J3ML/LinearAlgebra/Angle2D.hpp

@@ -0,0 +1,23 @@
+#pragma once
+#include "J3ML/J3ML.hpp"
+
+
+namespace J3ML::LinearAlgebra {
+
+    class Angle2D {
+    public:
+        float x;
+        float y;
+        Angle2D(Math::Rotation rads);
+        Angle2D(float X, float Y)
+        {
+            x = X;
+            y = Y;
+        }
+
+        bool operator==(const Angle2D& rhs) const {
+            return (this->x==rhs.x && this->y==rhs.y);
+        }
+    };
+
+}