swift2 ＋ iOS8以后的CoreData变动

try…catch

swift2以后引入了比较完整的try－catch异常的捕获机制，所以原来的error捕获全面变动：

// 原来的
if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {
  coordinator = nil
  // Report any error we got.
  var dict = [String: AnyObject]()
  dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
  dict[NSLocalizedFailureReasonErrorKey] = failureReason
  dict[NSUnderlyingErrorKey] = error
  error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
  // Replace this with code to handle the error appropriately.
  // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
  NSLog("Unresolved error \(error), \(error!.userInfo)")
  abort()
  }