title: MBProgressHUD armv7 error
body: <p>i'm trying to use MBProgressHUD. i added header an .m to project, imported header in class and call MBProgressHUD from an ibaction in this way:</p>
  
  <pre><code>-(IBAction)submitForm:(id)sender{
      MBProgressHUD *HUD = [[MBProgressHUD alloc] initWithView:self.view];
      [self.view addSubview:HUD];
      HUD.labelText = @"Connecting";
      [HUD show:YES];
  }
  </code></pre>
  
  <p>when i build project it happens an error:</p>
  
  <pre><code>Undefined symbols for architecture armv7:
      "_OBJC_CLASS_$_MBProgressHUD", referenced from:
      objc-class-ref in FormViewController.o
      ld: symbol(s) not found for architecture armv7
      collect2: ld returned 1 exit status
  </code></pre>
  
  <p>How can i fix it? can you help me?</p>