title: UIButton with rounded corners using square setBackgroundImage
body: <p>So I create a button.  I want it to have rounded corners with out making rounded .png files 
  I can set the background image ok.  I can round the corners ok.  However, when I set the background Image the rounded corners go away.  </p>
  
  <p>I did this once before a long time ago but can not seem to get it working again.  How can this be done?</p>
  
  <pre><code>UIButton *button1 = [UIButton buttonWithType:UIButtonTypeCustom];
  [button1 addTarget:self action:@selector(goSpecials)
    forControlEvents:UIControlEventTouchUpInside];
  [button1 setTitle:@"Specials" forState:UIControlStateNormal];
  button1.titleLabel.font = [UIFont fontWithName:@"Arial-BoldMT" size:(15.0)];
  [button1 setTitleColor:[self colorWithHexString:buttonColor] forState:UIControlStateNormal];
  button1.backgroundColor = [UIColor colorWithPatternImage: [UIImage imageNamed: @"button.png"]]; 
   //[button1 setBackgroundImage:[UIImage imageNamed:@"button.png"] forState:UIControlStateNormal];
  button1.frame = CGRectMake(20.0, 232.0, 135.0, 32.0);
  button1.layer.borderColor = [UIColor blackColor].CGColor;
  button1.layer.borderWidth = 0.5f;
  button1.layer.cornerRadius = 8.0f;
  [self.view addSubview:button1];
  </code></pre>
  
  <p>button.png: 
  <img src="https://i.stack.imgur.com/3XnDD.png" alt="enter image description here"></p>