title: Remove padding of content view in UITableViewCell though storyboard
body: <p>How to remove the default padding of content view in <code>UITableViewCell</code>? </p>
  
  <p>I put two label in the <code>UITableViewCell</code>'s content view, The content view has a gray background color.</p>
  
  <p>when I set top margin space between title and the content view to 0 (via constraint), the title is not align to the top!!! The same is leading and trailing space.</p>
  
  <p><img src="https://i.stack.imgur.com/HlZeS.png" alt="padding of content view in UITableCell"></p>
  
  <p>Here is my view struct:</p>
  
  <p><img src="https://i.stack.imgur.com/n1EDU.png" alt="enter image description here"></p>
  
  <p>I googled a lot, the answer in this <a href="https://stackoverflow.com/questions/5769184/remove-padding-on-uitableviewcell">post</a> works by overriding the <code>layoutSubviews</code> of UITableViewCell and setting frame of title manually.</p>
  
  <p>But can I do it in story board? or it there a attribute or something that controls the padding of the content view????</p>