don't allocate entire app on heap

src/main.cpp

@@ -2,16 +2,16 @@
 #include <MupenMovie.hpp>
 
 int main(int argc, char** argv) {
-  App* app = new App;
+  App app;
+
   if(argc > 1) {
     if(argc > 2) {
       LoadTAS(argv[2]);
     }
-    app->LoadROM(argv[1]);
+    app.LoadROM(argv[1]);
   }
 
-  app->Run();
+  app.Run();
 
-  delete app;
   return 0;
 }