call imgui shutdown functions

src/hexgame.cpp

@@ -266,9 +266,7 @@ processSDLEvents()
 bool
 cleanUp(SDL_Handles &handles)
 {
-#if 0
-	shutdownGooey();
-#endif
+	gooFree();
 	renFreeBuffers(g_render_state);	// renderer.h
 	for (SDL_Surface *surface : handles.texSurfaces)
 			SDL_FreeSurface(surface);