Revert "Engine: add quit function"

This reverts commit 2b5b455eb83508be62b743c7338e9fa831b36d6d.

platform/sfml/Graphics.cpp

@@ -1,6 +1,5 @@
 #include "Graphics.h"
 #include "sfwindow.h"
-#include "engine/main.h"
 #include <SFML/Graphics.hpp>
 #include "utility/misc.h"
 
@@ -34,12 +33,8 @@ void GRAPHICS::frame_end()
     sf::Event event;
     float scale = min(winsize.x / 320.f, winsize.y / 240.f);
 
-    while(window.pollEvent(event))
+    while (window.pollEvent(event))
     {
-        if (event.type == sf::Event::Closed)
-        {
-            WalrusRPG::quit();
-        }
     }
 
     window.setView(view = sf::View(sf::FloatRect(0, 0, winsize.x, winsize.y)));

src/engine/main.cpp

@@ -1,4 +1,3 @@
-#include "main.h"
 #include "StateMachine.h"
 #include "Timing.h"
 #include "Graphics.h"
@@ -80,13 +79,8 @@ int main(int argc, char *argv[])
     StateMachine machine(new States::StateMap(0, 0, map));
     machine.run();
 
-    quit();
-}
-
-void WalrusRPG::quit()
-{
     Quirks::deinit();
     Timing::deinit();
     Graphics::deinit();
-    exit(0);
+    return 0;
 }

src/engine/main.h

@@ -1,9 +0,0 @@
-#ifndef INCLUDE_MAIN_H
-#define INCLUDE_MAIN_H
-
-namespace WalrusRPG
-{
-    void quit();
-}
-
-#endif