use UNNotificationRequest for iOS

as iOS 10.1 is deprecating old notification reminder, it is good idea to switch the implementation to new API. This will make new feature in the future easy.

BREAKING CHANGE:
ios: The result of getScheduledNotifications will only contain the notification object you passed when you schedule notification. (now it only returns what was in data property
OLD:

{
   title: 'aaa',
   data: {
        title:'aaa'
   },
   action: null
}

NEW:

{
   title: 'aaa'
}