add FIXME/TODO for billboards

src/main.cpp

@@ -222,6 +222,12 @@ loadOrbit(GameState* gs,
 	scaleEntity(orbit->satellite_entity, 1 / SCALING);
 	setEntityPosition(orbit->satellite_entity, orbit->system.sat.position);
 
+	// FIXME: rotate satellite model to face camera
+	// TODO: billboards in libTangerine
+	//Camera* cam = rs->camera;
+	//Entity* sat = orbit->satellite_entity;
+	//*sat->model_xform = cam->xforms.view * sat->model_xform;
+
 	return orbit;
 }