title: Cannot convert value of type 'NSURL' to expected argument type 'String'
body: <p>In my code, I get the following errors:
  <code>// cannot convert value of type 'NSURL' to expected argument type 'String'</code> and
  <code>// Extra argument 'error' in call</code></p>
  
  <pre><code>class ScoreManager {
  var scores:Array&lt;Score&gt; = [];
  
  init() {
      // load existing high scores or set up an empty array
      let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
      let documentsURL = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0]
      let path = documentsURL.URLByAppendingPathComponent("Scores.plist")
      let fileManager = NSFileManager.defaultManager()
  
      // check if file exists
      if !fileManager.fileExistsAtPath(path) { // cannot convert value of type 'NSURL' to expected argument type 'String'
          // create an empty file if it doesn't exist
          if let bundle = NSBundle.mainBundle().pathForResource("DefaultFile", ofType: "plist") {
              fileManager.copyItemAtPath(bundle, toPath: path, error:nil) // Extra argument 'error' in call
          }
      }
  </code></pre>