Refresh subscriptions
Documentation and Refactoring of Validator
Add iOS restore
Handle a multi-transactions queue for each product
Remove the OWNED status when product expired
Fix handling of transaction queue on iOS
Retry validation 2 times
Delay validation till StoreKit retrieve new appStoreReceipt
Exponential validation retry delay
Restore transactions have an identifier
Recheck subscriptions each start iOS
Android error codes
Re-refresh on Android
Include receipt in Android transaction data
Add signature to getPurchases
Update android_iap submodule
Set version number 3.9.0-beta.1