The big NULL replacement party part 3.

Getting there I think.

src/arch/LoadingWindow/LoadingWindow_GtkModule.cpp

@@ -49,7 +49,7 @@ extern "C" const char *Init( int *argc, char ***argv )
 
 	gtk_widget_show_all(window);
 	gtk_main_iteration_do(FALSE);
-	return NULL;
+	return nullptr;
 }
 
 extern "C" void Shutdown()

src/arch/LoadingWindow/LoadingWindow_Win32.cpp

@@ -74,7 +74,7 @@ static HBITMAP LoadWin32Surface( RString sFile, HWND hWnd )
         RString error;
         RageSurface *pSurface = RageSurfaceUtils::LoadFile( sFile, error );
         if( pSurface == nullptr )
-                return NULL;
+                return nullptr;
 
         HBITMAP ret = LoadWin32Surface( pSurface, hWnd );
         delete pSurface;