1.0.0 - Ian

Feature/3 billing (#69)

* #3: New Billing Service repo and implementation

* #3: Clean up

* #3: Do not double check purchases array

* #3: Show toast upon completion

* #3: Add clicker for use inside xml

* #3: Tuning Billing

* #67: Simply catched crash in Consent Dialog

* #66: PurchasesList is now nullable

* #68: Check for empty hiscores

* #58: Update to release 1.0.0 Ian