title: Setting layoutMargins of UIView doesn't work
body: <p><code>UIViewController</code> with <code>UIView</code> and <code>UITableView</code></p>
  
  <pre><code>UIView
  |-UITableView
  </code></pre>
  
  <p>I'm trying to setup margins like this:</p>
  
  <pre><code>- (void)viewDidLoad {
      [super viewDidLoad];
  
      self.view.layoutMargins = UIEdgeInsetsMake(30, 30, 30, 30);
      self.tableView.preservesSuperviewLayoutMargins = YES;
      [self.view layoutIfNeeded];
  }
  </code></pre>
  
  <p>but nothing is happening on the view. </p>
  
  <p>Here are the constraints from InterfaceBuilder</p>
  
  <pre><code>(lldb) po self.view.constraints
  &lt;__NSArrayM 0x786ab6e0&gt;(
  &lt;NSLayoutConstraint:0x7896e940 UIView:0x7896e470.trailingMargin == UITableView:0x79b51a00.trailing - 16&gt;,
  &lt;NSLayoutConstraint:0x7896e970 UITableView:0x79b51a00.leading == UIView:0x7896e470.leadingMargin - 16&gt;,
  &lt;NSLayoutConstraint:0x7896e9a0 V:[_UILayoutGuide:0x7896e510]-(0)-[UITableView:0x79b51a00]&gt;,
  &lt;NSLayoutConstraint:0x7896e9d0 V:[UITableView:0x79b51a00]-(0)-[_UILayoutGuide:0x7896e600]&gt;,
  &lt;_UILayoutSupportConstraint:0x7896c7d0 V:[_UILayoutGuide:0x7896e510(0)]&gt;,
  &lt;_UILayoutSupportConstraint:0x7896c2b0 V:|-(0)-[_UILayoutGuide:0x7896e510]   (Names: '|':UIView:0x7896e470 )&gt;,
  &lt;_UILayoutSupportConstraint:0x7896cbf0 V:[_UILayoutGuide:0x7896e600(0)]&gt;,
  &lt;_UILayoutSupportConstraint:0x7896ea00 _UILayoutGuide:0x7896e600.bottom == UIView:0x7896e470.bottom&gt;
  )
  </code></pre>
  
  <p>as a result don't see any margins, nothing is changed at all.... What I'm issing ?</p>
  
  <p>iOS 8</p>