title: NSTextField non-system-font content clipped when usesSingleLineMode is true
body: <p>Setting usesSingleLineMode to true for a non-system font causes the top of the text to be clipped.</p>
  
  <p>I've created 3 very simple test cases that illustrate this:</p>
  
  <ul>
  <li><em>good</em> : non-system font, with usesSingleLineMode = false. Works fine.</li>
  <li><em>bad</em> : non-system font with usesSingleLineMode = true. Does not work.</li>
  <li><em>system</em> : system font with usesSingleLineMode = true. Works fine.</li>
  </ul>
  
  <p>Add the following to the viewDidLoad() method of a new Cocoa OSX application:</p>
  
  <pre><code>// Do any additional setup after loading the view.
  let good = NSTextField(frame: NSRect(x: 0, y: 0, width: 800, height: 55))
  good.usesSingleLineMode = false
  good.font = NSFont(name: "HelveticaNeue-UltraLight", size: 24)
  good.stringValue = "Good usesSingleLineMode false "
  self.view.addSubview(good)
  
  let bad = NSTextField(frame: NSRect(x: 0, y: 100, width: 800, height: 55))
  bad.usesSingleLineMode = true
  bad.font = NSFont(name: "HelveticaNeue-UltraLight", size: 24)
  bad.stringValue = "Bad usesSingleLineMode true"
  self.view.addSubview(bad)
  
  let system = NSTextField(frame: NSRect(x: 0, y: 200, width: 800, height: 55))
  system.usesSingleLineMode = true
  system.font = NSFont.systemFontOfSize(24)
  system.stringValue = "Good usesSingleLineMode true, System Font"
  self.view.addSubview(system)
  </code></pre>
  
  <p><img src="https://i.imgur.com/kyxj66f.png" alt="See the result"></p>
  
  <p>If I create the same <code>bad</code> NSTextField using Interface Builder in a storyboard, set the font in IB and check Uses Single Line Mode in IB it works fine! But, it would be impractical to build the overall view in IB, thus I want to programmatically create it.</p>
  
  <p>Why is this happening? Have I missed some important setting (I've tried adjusting many NSTextField and NSTextFieldCell parameters to no avail? Is there a workaround?</p>