Release 1.13: Bug fix - Steam process continues to run

The following enhancements are included in version 1.13:

1. If the game is closed with “Alt-F4”, the Steam process continues to run. This bug is fixed in the Steam integration.
   
2. a small translation error in the main menu is fixed
   
3. if Steam has not been initialized correctly, only the “Exit” button is active in the main menu