* added basic logic to early exit restoreTransactions if there are no transactions on the receipt

* made ReceiptParser public, added a method to check if a receipt has transactions, used it to decide whether or not to post the receipt

* added tests for receiptHasTransactions

* injected ReceiptParser through DI for testing purposes

* added tests to ensure that post gets called in the right circumstances

* updated so that receiptHasTransactions returns true if the receipt can't be parsed

* updated the carthage build step since we now have two schemes

* update fastlane

* removed xcframeworks plugin since it's not compatible with static libraries

* fix a race condition when syncing subscriber attributes after launching the app

* updated so that 404s on subscriber attributes won't mark attributes as synced.

* reverted changed for successfullySyncedKey since they're a part of another PR already

* cleanup, removed duplicate declaration of operationDispatcher, added forward-declaration in extension header

* added test to ensure that subscriber attributes sync happens after purchaser info sync

* added more expectations

…tored in wrong path (#330)