iOS SDK 3.1.1

Improvements

Add customizable interval in LPRequestSenderTimer (#413)
Add method for downloading inbox messages (docs) (#416)
Refactor batching of requests (#413)
Resource bundle support (#412)

Fixes

Open URL encoding (#415)
Using UNUserNotification instead of deprecated UILocalNotification class (#411)
Chained rich interstitial messages fix for iOS 12 (#410)