refactors interface to be more blockchain agnostic and more intuitive
introduces returning spies when mock is called in order to exepect toHaveBeenCalled on mocks
introduces explicit helpers to confirm a mocked transaction and to increaseBlock in order to execute code that requires a certain amount of confirmations
mockis called in order to exepecttoHaveBeenCalledon mocksconfirma mocked transaction and toincreaseBlockin order to execute code that requires a certain amount of confirmations