The game has a Results screen

[TheoPannetier]

Context

When the game is over, we need to display a screen to let the players know who has won this round. A first step is to create a structure for this screen.
First, decide what kind of screen we want: a window that shows up in the middle of the Game view? A new full-screen view? A pop-up? Once you have decided, make sure to write a test to ensure this screen exists.
The actual contents of the screen can be dealt with afterwards.

Test

I have added a draft test in game_view.cpp, feel free to change it to match your idea of the results screen

#ifdef FIX_ISSUE_718
  // (718) A game_view has a Results screen
  {
    game_view gv;
    gv.get_results_screen();
  }
  #endif // FIX_ISSUE_718

[TheoPannetier]

Done, the game now has a results screen

[TheoPannetier]

I lied