Added NotificationCenter post when keys have finished synchronization…

… from iCloud. (#36)

Sources/Zephyr.swift

@@ -7,6 +7,7 @@
 //
 
 import Foundation
+import UIKit
 
 /// Enumerates the Local (`UserDefaults`) and Remote (`NSUNSUbiquitousKeyValueStore`) data stores
 private enum ZephyrDataStore {
@@ -26,6 +27,9 @@ public final class Zephyr: NSObject {
     /// If **true**, then `NSUbiquitousKeyValueStore.synchronize()` will be called immediately after any change is made.
     public static var syncUbiquitousKeyValueStoreOnChange = true
 
+    /// A string containing the notification name that will be psoted when Zephyr receives updated data from iCloud
+    public static let keysDidChangeOnCloudNotification = Notification.Name("ZephyrKeysDidChangeOnCloudNotification")
+
     /// The singleton for Zephyr.
     private static let shared = Zephyr()
 
@@ -435,6 +439,9 @@ extension Zephyr {
             for key in monitoredKeys where cloudKeys.contains(key) {
                 syncSpecificKeys(keys: [key], dataStore: .remote)
             }
+
+            // Notify any observers that we have finished synchronizing an update from iCloud
+            NotificationCenter.default.post(name: Zephyr.keysDidChangeOnCloudNotification, object: nil)
         }
     }