This allows us to construct menus in a more natural way:
auto& file_menu = menubar->add_menu("File");
file_menu.add_action(...);
Instead of the old way:
auto file_menu = GUI::Menu::construct();
file_menu->add_action(...);
menubar->add_menu(file_menu);
Added a solitaire game. Currently there are graphics missing on some
of the cards, but the game is fully functional.
Press F12 to show the game-over animation manually.
