Issue #216 : add a property inside PacoClient to indicate if it’s the first time that user launches our app. If it’s first launch, then cancel all notifications and delete keychain cache
Issue #216 : add two unit tests
Issue #220: add code of executing major task
Issue #220 : add new category methods to NSString and NSError, add unit tests
Issue #574 : load notifications after data model is loaded, instead of inside the init method of PacoScheduler; perform major task after notifications are loaded; ignore the file not existing error when there is no notification plist