* MOS-13:
  MOS-13 Add notification property in product before 10.14 and all related refactor.
  MOS-13 Refactor parameter in removeDeliveredNotifications.
  MOS-13 Remove delivered notifications from a single product instead of all products.
  MOS-13 Fix install update in menu. Add notify function for os versions prior to 10.14 where notification object is needed. Add removeDeliveredNotifications function in DownloadNotificationManager.

* Release_2.1:
  MOS-11 Change menu title to 'p≡p updates'. Change menu item title to 'Check for Updates'. Change menu item title to 'Keep software up to date'.
  MOS-9 Change statusBarITem to variableLength so we can see the menu text properly.
  MOS-8 Rename menuitems properties.
  MOS-8 Split to extensions. Create PEPNotification. Refactor.
  MOS-8 Change pEpMacOSAdapterProtocol to PEPMacOSAdapterProtocol.
  MOS-8 Change pEpNotificationProtocol to PEPNotificationProtocol.
  MOS-8 Create DownloadStateNotifier, which is responsible to show state messages in statusText menu item.
  MOS-8 Split applicationDidFinishLaunching to private functions to improve readability.
  MOS-8 Delete @objc and add private to removeDeliveredNotifications.
  MOS-8 localizedStringWithFormat to String.
  MOS-8 Add guard when needed. Change else statements to right place.
  MOS-8 Add lazy to connection and related changes.
  MOS-8 Remove ! from clientListener and related changes.
  MOS-8 Remove ! from service and related changes.
  MOS-8 Remove ! from connection and related changes.
  MOS-8 Delete self when not needed. Move comments for removeDeliveredNotifications.
  MOS-8 Delete all previous product notifications before sending a new one.

* MOS-11:
  MOS-11 Change menu title to 'p≡p updates'. Change menu item title to 'Check for Updates'. Change menu item title to 'Keep software up to date'.