Start refactor, restructure basic

src/basic/math.cpp

@@ -1,41 +1,3 @@
-struct Vec2 {
-    float x;
-    float y;
-};
-
-union Vec4 {
-    struct {
-        float x;
-        float y;
-        float z;
-        float w;
-    };
-    struct {
-        float r;
-        float g;
-        float b;
-        float a;
-    };
-};
-
-union Vec3 {
-    struct {
-        float x;
-        float y;
-        float z;
-    };
-    struct {
-        float r;
-        float g;
-        float b;
-    };
-};
-
-struct Rect2 {
-    Vec2 min;
-    Vec2 max;
-};
-
 Vec2 GetSize(Rect2 r) {
     Vec2 result = {r.max.x - r.min.x, r.max.y - r.min.y};
     return result;