title: UIScrollView not scrolling although contentSize is smaller than UIImageView
body: <p>So I have a <code>UIImageView</code> as a subview of <code>UIScrollView</code>, I've set the <code>contentSize</code> to be smaller than the <code>UIImageView</code> width and height, however it doesn't allow me to scroll.. why is this? Here's some code:</p>
  
  <pre><code>UIImage * image = [UIImage imageWithData:data];
                  UIImageView * imgView = [[UIImageView alloc] initWithImage:image];
                  [imgView setUserInteractionEnabled:YES];
                  //[imgView setContentMode:UIViewContentModeScaleAspectFill];
                  [imgView setBackgroundColor:[UIColor clearColor]];
                  [imgView setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight];
                  [imgView setFrame:CGRectMake(0, 0, imgView.frame.size.width, imgView.frame.size.height)];
  
                  CGRect imgFrame;
                  imgFrame.size.width = originalImageSize.width;
                  imgFrame.size.height = originalImageSize.height;
                  imgFrame.origin.x = imageOriginPoint.x;
                  imgFrame.origin.y = imageOriginPoint.y;
  
                  UIScrollView * imgScrollView = [[UIScrollView alloc] initWithFrame:imgFrame];
                  [imgScrollView setScrollEnabled:YES];
                  [imgScrollView setClipsToBounds:YES];
                  [imgScrollView addSubview:imgView];
                  [imgScrollView setBackgroundColor:[UIColor clearColor]];
  
  
    [imgScrollView setFrame:imgFrame];
                  [imgScrollView setContentSize:CGSizeMake(200, 200)];
  
  SCROLL VIEW CONTENT SIZE WIDTH IS 200.000000 AND HEIGHT CONTENT SIZE IS 200.000000
  UIIMAGE VIEW WIDTH IS 2240.225830 AND HEIGHT IS 2240.225830
  SCROLL VIEW FRAME WIDTH IS 768.000000 AND SCROLL VIEW FRAME HEIGHT IS 768.000061
  </code></pre>
  
  <p>Any idea?</p>