Add function to exit the game

include/GameEngine.h

@@ -27,6 +27,7 @@ bool init_engine(const char *game_name, WindowSize window_size,
                  u8 audio_tracks);
 
 bool game_running();
+void stop_game();
 void close_engine();
 
 i64 get_time();

src/GameEngine.c

@@ -149,6 +149,8 @@ bool init_engine(const char *game_name, WindowSize window_size,
 
 bool game_running() { return GameEngine.running; }
 
+void stop_game() { GameEngine.running = false; }
+
 void close_engine() {
   destroy_asset_manager(&(GameEngine.asset_manager));