title: self.delegate is ignored when I use delegate, may I ask the reason why?
body: <p>I want to delegate my method through <code>[self.delegate showShareScreen]</code> in GameOverScene.m, but I can't delegate that. I would like to know the reason why and solve it.
  Working image is that there is a twitter image in Game Over Scene. When I touch it, it will work and twitter share screen will appear and I can use it.</p>
  
  <p>GameOverScene.h</p>
  
  <pre><code>#import  &lt;SpriteKit/SpriteKit.h&gt;
  
  @protocol sceneDelegate &lt;NSObject&gt;
  -(void)showShareScreen;
  @end
  @interface GameOverScene : SKScene
  @property (weak, nonatomic) id &lt;sceneDelegate&gt; delegate;
  - (id)init;
  @end
  </code></pre>
  
  <p>GameOverScene.m</p>
  
  <pre><code>#import "GameOverScene.h"
  #import "NewGameScene.h"
  #import "MainScene.h"
  #import &lt;Social/Social.h&gt;
  
  @implementation GameOverScene
  
  @synthesize delegate;
  
  - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
  {
  
  UITouch *touch = [touches anyObject];
  CGPoint location = [touch locationInNode:self];
  SKNode *node = [self nodeAtPoint:location];
  
  if([node.name isEqualToString:@"twitterbutton"]){
        [self.delegate showShareScreen];
        //When I use the breakpoint, it is ignored.**
     }
   }
  </code></pre>
  
  <p>ViewController.h</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  #import &lt;SpriteKit/SpriteKit.h&gt;
  #import &lt;iAd/iAd.h&gt;
  #import "GameOverScene.h"
  
  @interface ViewController : UIViewController &lt;sceneDelegate&gt;
  
  @end
  </code></pre>
  
  <p>ViewController.m</p>
  
  <pre><code>#import "ViewController.h"
  #import "NewGameScene.h"
  #import &lt;Social/Social.h&gt;
  #import "GameOverScene.h"
  
  @interface ViewController ()
  
  @end
  
  @implementation ViewController
  
  - (void)loadView
  {
  self.view  = [[SKView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
  GameOverScene *theScene = [[GameOverScene alloc]init];
  theScene.delegate = self;
  }
  
  -(void)showShareScreen
  { 
  if ([SLComposeViewController isAvailableForServiceType:SLServiceTypeTwitter])
  {
      SLComposeViewController *tweetSheet = [SLComposeViewController
                                                  composeViewControllerForServiceType:SLServiceTypeTwitter];
      [tweetSheet setInitialText:@"TestTweet from the Game !!"];
      [self presentViewController:tweetSheet animated:YES completion:nil];
  
  }
  }
  
  @end
  </code></pre>